Treatment of  Skin Diseases – Different Modalities

Treatment of  skin diseases consists of  systemic drugs, local drugs and other local therapies.

Local applications play a big role in treatment of skin diseases.

Some conditions require only local treatment, others require a combination of local treatment with systemically given drugs, while occasionally, systemically administered drugs alone are sufficient.

Then there are other modalities like surgical, electro-surgical or other measures.

Local Measures for Treatment of Skin Diseases

A large number of patients can be treated with local therapy alone. This makes the therapy much safer, because:

• The side effects of locally applied medicines are generally quite negligible, milder and safer.
• Local concentrations of drugs can be achieved effectively.
• Few drug cannot be given systemically but local formulation may be applied

Local therapeutic measures come under the following categories:

Compresses, Soaks and Baths

Compresses, soaks and baths are a very useful adjuvant to locally applied medicines and should be used for all diseases associated with inflammation and exudation. These help in mechanically removing the exudates, loose and poorly formed crusts, fragments of dead tissue and remnants of previously applied medicines.

It has also been observed that locally applied medicines act much better if used after compresses, soaks or baths. The medicines added to the water used for compresses, soaks and baths, have an additional therapeutic value.

Compresses

For compresses one should take a piece of clean cloth or lint measuring about 20 cm square and soak it in the solution prepared for the compresses. After squeezing the cloth to remove the excess solution, it should be pressed over the lesion for a few seconds.

This cloth should again be dipped in the solution, squeezed and pressed over the lesion for a few more seconds. This procedure can be continued for five to ten minutes, twice or thrice a day depending upon the requirements.

Soaks

Soaks are indicated when it is required to have a prolonged action of some medicine on the lesion. These can be conveniently done only if the lesions are situated on the hands, feet, forearms or legs. In this case, the solution should be prepared in a basin if the lesions are located on the hand or feet, or in a bucket if the legs or forearms are involved.

The container should be filled to half its capacity with the medicated solution and the patient should dip the part in the solution for half an hour or so. A gentle massage over the lesion, while it is immersed in the solution, ensures proper penetration of the medicines.

Baths

Baths act like soaks and are indicated when the lesions are generalized. In this case, one should select a bathing tub of a size large enough to accommodate the patient and fill it half with the medicated solution. The patient should lie in the tub for approximately half an hour and gently massage the lesions as these are immersed in the medicated solution.

Preparing the bath water in a bucket and pouring water on the body or lesion as during ordinary bucket bath is of no use, because it is essential to keep the solution in contact with the skin lesion for an adequate period of time.

Solutions For Compresses, Soaks Or Baths

For preparing the solution for compresses, soaks or baths, tap water should be used either as such or preferably warmed to a temperature well within the limits of tolerance of the skin. The warmth of the water helps in improving the circulation which brings in fresh nutrition and immunity, and removes the products of inflammation and tissue damage.

Iice-cold compresses are recommended for acutely inflamed lesion. The low temperature leads to vasoconstriction and may help in reducing the edema, but if the temperature of the water is very low, the initial vasoconstriction is usually followed by a reactive vasodilation which is likely to aggravate the edema and pain..

The following medicines added to the water for compresses, soaks or baths enhance their therapeutic value

Potassium permanganate

It is a good oxidizing agent and in a concentration of 0.01 percent, it is useful for compresses on lesions associated with exudation or necrosis. It is not necessary to be extremely accurate for making the solution; generally, potassium permanganate added in a quantity to make a light magenta color is sufficient.

During the compresses, potassium permanganate changes to manganese dioxide which is brownish in colour. Therefore, a change in the colour of the solution from magenta to brown indicates that the solution is no more effective and it should be changed.

Normal saline

Ordinary common salt (sodium chloride), in a concentration of 0.9 percent is isotonic with the tissues and therefore has a soothing effect on raw areas and acutely inflamed lesions.

Half to one level teaspoonful of common salt added to a glass (approximately 250 ml) of warm water makes approximately normal saline which can be used for compresses. Too low or too high a concentration are both likely to irritate the inflamed skin.

Hypertonic saline

This can be made by adding two or three level teaspoonfuls of common salt to a glass of warm water or 0.25 kg salt to half a bucket (20 litres capacity) of water, or 1 kg of salt to half a tub (100 litres capacity) of water. This is useful for lichenified or hyperkeratotic lesions.

Sodium bicarbonate

Sodium bicarbonate has a weak keratolytic effect. Soaks prepared by adding five level teaspoonfuls of sodium bicarbonate to half a basin of water can be used for treating patients having dermatophytosis of the palms or soles or those having hyperkeratosis due to other causes.

These are the agents commonly employed for compresses, soaks or baths but depending upon the indications, other medicines or agents can also be used.

Drugs in Local Therapy

Some common topical treatments for skin conditions include:

Antibacterials

Medicines like muprocin  and clindamycine. These are often used to treat or prevent infection.

Antifungal agents

Terbinafine, clotrimazole, and ketoconazole are few of antifungal agents used topically.

Benzoyl peroxide

Creams and other products containing benzoyl peroxide are used to treat acne.

Gentian violent and Brilliant Green

In acute inflammations, applications of a one per cent aqueous solution of either of these two dyes are quite effective in controlling the acute inflammatory process even when there is a good deal of exudation. The only disadvantage with these dyes is their colour.

The dressing has to be changed once or twice a day.

Corticosteroids

These are frequentlu used in treatment of skin used to treat skin conditions. These are available in many different like lotions, ointments, and creams.

Retinoids

These are derived from vitamin A and are used to treat conditions including acne.

Salicylic acid

This drug is sold in lotions, gels, soaps, shampoos, and patches. Salicylic acid is the active ingredient in many skin care products for the treatment of acne and warts.

Systemic Drugs – Oral and Injectibles

When the drug is given through oral or via injections so that it reaches the diseased part after getting into blood circulation, this mode of therapy is called systemic therapy.

Systemic administration results in a generalized distribution of the drug throughout the body and is necessary:

• When the disease produces widespread lesions which are difficult to treat by local medicines alone.
• When the lesions are situated more deeply where locally applied medicines are ineffective.
• When the disease is producing systemic effects such as fever.
• When there is concomitant involvement of other organs of the body and
• 5. When the locally applied medicines are unable to control the disease or prevent the appearance of new lesions.

These drugs are given either orally or by subcutaneous, intramuscular or intravenous injections. For oral administration, only those drugs can be used which are absorbed from the gastro-intestinal tract and which are not destroyed by the digestive juices.

The drug, however, takes some time usually 20-30 minutes, to be absorbed from the gastro-intestinal tract and reach the site of action. Moreover, disturbances of the gastro-intestinal tract are liable to interfere with the absorption of the drug.

For instantaneous action, the drug should be given by injection, but care must be taken to sue perfect aseptic techniques.

Antibiotics

Antibiotics are important agents to fight infection. They are used in injectible form and oral drugs

Antifungal agents

Oral antifungals have changed the way fungal  infections of skin are treated. Larger infections now can be easily controled. Ketoconazole, fluconazole are commonly used durgs.

Antiviral agents

Common antiviral agents include valacyclovir, acyclovir, and famciclovir. These are used in treatment of skin diseases like herpes

Corticosteroids

Steroids are helpful in autoimmune diseases and inflammatory diseases.

Immunosuppressants

Azathioprine and methotrexate, are used in conditions like psoriasis.

Biologics

These are new drugs utilized to treat psoriasis and other conditions. Examples of biologics include adalimumab , etanercept , inflixirnab, and secukinumab, and ustekinumab.

Enzyme inhibitors

Apremilast is an enzyme inhibitor used to curb inflammation.

Retinoids

Acetretin is used in severe psoriasis and acts to reduce skin cell growth.  It should be avoided in pregnant and lactating women as it causes severe birth defects.

Anti-Malarials

Drugs like quinine, mepacrine and chloroquine, apart from their activity as anti-malarials, have been found to be excellent sunscreens when given systemically.

Chloroquine therefore has been found to be particularly useful in discoid lupus erythematosus and polymorphous light sensitive eruptions.

Intralesional Injection For Skin Diseases

One of the limitations of topically applied medicines is their restricted ability to cross the epidermal barrier. In specialized circumstances therefore, one of the following procedures can be used to enhance the effect of locally applied medicines.

By an intralessional injection, a drug can be deposited directly at a place where it is required to act. For this purpose, a high concentration is used so that a large dose of the drug can be deposited by injecting a small volume of the vehicle.

The injection should be given by a 24 or 26 gauge hypodermic needle with an appropriate sized syringe and an attempt should be made to deposit the drug as uniformly in the lesion as possible.

This mode of treatment, however, can be employed for treating a few lesions only.

Corticosteroids are the most commonly used drugs for intralesional therapy. These have been used for the treatment of resistant lesions of psoriasis, pemphigus, hypertrophic lichen planus, lichen simplex chronicus, alopecia areata and keloids.

Repeated injections of corticosteroids frequently lead to an atrophic change in the skin.

Intralesional injections are extremely painful especially when given in areas where the tissues are not loose.

Surgery in Treatment of Skin Diseases

Surgery for skin lesion is considered when  medicinal therapy is ineffective or if the patient desires a quick result which cannot be achieved by medicinal treatment.

The lesions/diseases which require surgical procedures include:

• Benign lesions such as warts, molluscum contagiosum, corns, granuloma pyogenicum, melanocytic, vascular or epidermal naevi, adenoma sebaceum, trichoepithelioma, syringoma, cysts, milia and xanthelasma,
• Malignant tumours such as malignant melanoma, squamous cell or basal cell epitheliomas
• Resistant lesions of vitiligo, male pattern baldness, cicatrical alopecia, acne comedones, cystic acne, and
• Scars produced by any disease especially small pox, acne, burns or other injuries.

Various procedures which can be adopted in such cases include:

• Chemo-surgery which involves destruction of the lesion with cauterizing chemicals
• Electro-surgery which involves destruction of tissues with electrically heated electrodes or with electric current
• Cryo-surgery involving destruction of the lesions with cold
• Laser-surgery involving destruction with lasers
• Surgery with simple excision of the tissues

Surgical Excision

Small tumours or cysts can be easily taken out by surgical excision.

Surgical excision can also be undertaken for the keloids and scars left over by the skin lesions or such lesions which cannot be treated with medicines.

Electrolysis

This is the only method available so far, for permanent removal of supernumerary hairs.

The main purpose of electrolysis is to destroy the hair bulb and its dermal papilla. This can be achieved by means of an apparatus which uses direct current  and causes ionization and accumulation of sodium ions at the negative pole i.e. the needle electrode.

Sodium ions react with water and produce sodium hydroxide which destroys the tissue. This procedure is painless

After the current has been switched off, the needle should be removed and the hair should be pulled out by means of an epilating forceps.

Cryosurgery

Cryosurgery or cryotherapy is the application of extreme cold to destroy abnormal or diseased tissue. The term comes from the Greek words cryo which means icy cold.

Cryosurgery is used to treat a number of diseases and disorders, especially a variety of benign and malignant skin conditions. Skin lesions such as warts, molluscum contagiosum, cutaneous tags, seborrhoeic keratosis, adenoma sebaceum, epidermal and vascular nevi etc. can also be destroyed by freezing.

The commonly used for this purpose are

• Carbon dioxide snow (boiling point, 78.5 degree Celsius)
• Liquid nitrogen (boiling point, – 194 degree Celsius) which are generally available from companies dealing with industrial gases.

Freezing destroys the by

• Producing intracellular and intercellular ice crystals
• Causing osmotic and electrolyte changes
• Blocking the blood vessels supplying blood to the tissues.

LASER

Lasers  techniques use a high intensity light to destroy or cut through the tissues.

There are a variety of lasers used in destruction of skin lesions

• Ruby lasers
• Argon lasers
• Carbon dioxide laser
• Rhubidium laser

There are many other types of lasers and each laser has an advantage over the other types for destroying a specific type of a lesion.

The laser gives a better scarring following laser therapy. Apart from skin disorders, laser has found an increasing role in cosmetic therapy.

The lesions which are commonly treated with lasers include capillary hemangiomas, pigmented nevi, telangiectasias, and other benign and malignant lesions.

Few Drugs Used in Treatment of Skin Diseases

Methotrexate

This is a folic acid antagonist which acts by blocking the action of folic acid reductase. This has been extensively used in patients having psoriasis, pemphigus and pemphigoid with beneficial results. Generally, three dosage schedules are employed:

1. A daily oral dose of 2.5 to 5 mg
2. A weekly intramuscular or intravenous injection of 25 mg, and
3. Once a week three 12 hourly oral doses, each consisting of 5 to 10 mg.

The side effects include nausea, vomiting, loss of appetite, severe headache, leucopaenia, pancytopaenia, superadded infections, gastro-intestinal bleeding and mucosal ulcers. The most serious side effect, however, are, insidiously progressive liver damage leading to cirrhosis and progressive renal failure.

Late onset of cirrhosis which is usually discovered at a stage when nothing can be done to save the patient, has led many physicians to abandon the use of methotrexate in favour of other immunosuppressive agents.

Cyclophosphamide

This is a relatively much safer drug in the sense that its side effects are fewer, less serious and reversible. It can be used either by intravenous injection giving 200 mg daily or 500 mg once a week, or orally in the form of 50 mg tablets giving 50-200 mg a day depending upon the severity of the condition.

It has been used for patients having psoriasis, pemphigus, pemphigoid and systemic lupus erythematosus. The therapeutic effect is slow. In severe cases, it may be combined with corticosteroids.

The side effects include leucopaenia, loss of appetite, vomiting, diarrhea, loss of hair, fever, mucous membrane ulcerations, cystitis, haematuria and superadded infections. A regular check on the total and different leucocyte counts should be made during the treatment, especially when the patient is on higher doses.

If total leucocyte count falls below 2000 cells/cmm should, the therapy should be stopped  till the count rises again to normal levels. Similarly, occurrence of other side effects indicates temporary suspension of treatment.

Some individuals tolerate cyclophosphamide even in low doses. These patients should preferably be treated with other drugs. Very high doses may lead to azoospermia or amenorrhoea.

Azathioprine: Clinical experience with azathioprine is as yet quite scanty. It has been used in doses of 2.5 mg/kg body weight in patients having psoriasis, pemphigus or pemphigoid.

The major side effects include leucopaenia, gastro-intestinal upsets, mucosal ulcerations and hepatotoxicity with cholestatic jaundice.

Corticosteroids In Systemic Therapy

Corticosteroids are a group of substances which were originally discovered as hormones produced by adrenal cortex. Now however, a large number of chemical substances have been synthesized with several modifications in the original formula.

All these chemicals have biological properties similar to the original hormones, but these compounds are far more potent. Their relative potencies in terms of biological activity are:

Cortisone – 25 (equivalent potency in mg)
Hydrocortisone – 20 (equivalent potency in mg)
Prednisone – 5 (equivalent potency in mg)
Prednisolone – 5 (equivalent potency in mg)
Triamcinolone – 4 (equivalent potency in mg)
Dexamethasone – 0.7* (equivalent potency in mg)
Betamethasone – 0.7* (equivalent potency in mg)

For therapeutic use, however, 0.5 mg of dexamethasone or betamethasone is considered to be equivalent to 25 mg of cortisone.
Therapeutically, all these compounds are very potent anti-inflammatory, anti-allergic and immuno-suppressive agents. Thus, they can be used for the treatment of various types of allergic and auto-immune disorders.

Not only do they impede the formation of antibodies and sensitized lymphocytes, but they also interfere with the after-effects of antigen-antibody reactions. They can also be used in inflammatory diseases caused by infectious agents, provided therapy with a specific anti-infective agent is also given simultaneously.

In such instances, corticosteroids curtail the inflammatory response and thus, reduce the residual damage left by the disease process. During recent years, corticosteroids have been found to be useful even in vitiligo.

There are no well defined dosage schedules of corticosteroids. These vary from physician to physician. The most important factor doses which should be continued as long as the disease is active.

When, however, the disease becomes quiescent, the corticosteroids can be withdrawn, but this should not be done abruptly. All corticosteroids have similar properties and given in equivalent doses, they are equally effective.

Costisone and hydrocortisone however, are short-acting, prednisolone and triamcinolone are intermediate-acting, while dexamethasone and betamethasone are long-acting. The more potent corticosteroids have fewer side effects.

Occasionally, when a patient is not responding to an apparently adequate dose of one type of corticosteroid, a change over to another corticosteroid in an equivalent dose may bring the disease under control.

Anti Bacterial Agents

Anti bacterials act either  by  killing the bacteria and are therefore, called bactericidal drugs or  inhibit their proliferation and are called bacteriostatic drugs.

Most of these drugs act against a large variety of organisms and therefore, have a broad spectrum of activity, while others have a narrow spectrum.

Resistance is a problem with antibacterial agents and this happens more frequently with certain anti-bacterial agents than with others, more so, if the patient had been given subtherapeutic doses of the agent. Generally, an anti-bacterial agent should be able to control the symptoms within 2 days and eradicate the infection with 5-7 days, after which further treatment with the anti-bacteria agent can be stopped.

In case there is no improvement within 2 days, one should suspect resistance of the causative organism to the anti-bacterial agent. More appropriately, however, the causative organisms should be cultured in vitro to determine the sensitivity (susceptibility) pattern of the organism to various anti-bacterial drugs, and use the mot effective drug.

The anti-bacterial drug must be used in the prescribed dosage and continued till the infection has been completely eradicated. The exact duration of treatment will depend upon the type of infection, but it is preferable to treat a patient for a longer duration rather than stop the treatment too early.

It is a serious mistake to use anti-bacterial agents in smaller dosages, or to miss some doses, or taper the dose after the infection has been controlled, because these practices help the bacteria to develop resistance against the anti-bacterial agent which will become useless for further use in the same patient as well as others.

Some patients develop toxic or allergic reactions following treatment with anti-bacterial agents. It is a good practice therefore, to ask every patient beforehand, it he ever developed any reaction following treatment with an anti-bacterial agent on a previous occasion.

A description of some of the commonly used anti-bacterial agents follows. The doses have been expressed as for adults; for children and infants, however, one half and one quarter of the adult dose respectively, as a rule, suffices.

Sulphonamides: These are a group of bacteriostatic agents which act by substrate competition with para-aminobenzoic acid and are active against common pyogenic organisms such as staphylococci, streptococci and E. coli, though several strains of staphylococcus have now acquired resistance to these agents.

The commonly used sulphonamides include sulphadiazine, sulphadimidine, sulphathiazole and sulphamerazine and there is very little to choose between them. Each of these drugs is available as 0.5 gm tablets and the therapeutic dose consists of two tablets thrice a day.

The long acting sulphonamides are given in the following doses: sulphaphenazole, one tablet twice a day; sulphadimethoxone, one tablet daily; and sulphamethoxazole-trimethoprim, two tablets twice a day or one double strength tablet twice a day. The most frequent side effect includes crystalluria, fixed drug eruption, photosensitivity, keucopaenia and generalized skin rashes, but these are not very common.

In order to prevent crystalluria, the patient should be advised to take a full glass of water with every dose of the drug. Should the patient develop any other side effect, these drugs must be discontinued and the patient treated with an alternative anti-bacterial agent. Patients having photosensitivity or any other dermatosis aggravated by sunlight should not be treated with sulphonamides.

Penicillin:Penicillins interfere with the synthesis of bacterial cell wall and thus are bactericidal drugs. However, they have only a limited range of activity. These are effective against Gram positive and Gram negative cocci and some Gram positive bacilli. These are useful mainly in infections caused by staphylococcus and streptococcus, but several strains of staphylococcus have developed resistance against penicillins.

Some organisms acquire the potential of producing penicillinase (betalactamase) enzyme, and become resistant to penicillins. In spite of their drawbacks, however, penicillins still continue to be the most widely used drugs for the treatment of bacterial infections. They are mostly administered by the intramuscular route.

One can give either 500,000 units of crystalline penicillin twice a day or employ one of the long-acting penicillins which include: (1) procaine penicillin, in a dose of 400,000 units once a day, (2) procaine penicillin with aluminium monosterate (PAM), giving 600,000 units on alternate days, or once in a fortnight if at all required to be repeated. Penicillin is also available in the form of tablets for oral use which can be given in a dose of 130 mg four times a day.

The chief side effects of penicillins are their hypersensitivity reactions, which include anaphylaxis, urtricaria and papulo-vesicular rashes. Out of these, anaphylaxis is the most serious side effect which may lead to a fatal termination within a few seconds. When using penicillins therefore, it is always a wise routine to test the patient for hypersensitivity before starting the treatment.

This test can be done by injecting 0.01 ml of a solution containing 50,000 units of penicillin intradermally on the forearm skin along with a saline control on the other forearm. If within 30 minutes, the test site develops a wheal which is more than one and a half times the size of the control wheal the patient should not be given penicillin.

Occasionally, even the test dose of penicillin has been observed to produce fatal anaphylaxis. Therefore, patients who on an earlier occasion had experienced manifestations suggestive of anaphylaxis following penicillin, should first be tested with 10,000 units of penicillin and if this test is negative, one can proceed to test with 50,000 units.

Alternatively, the patient can be tested with the scratch test which is performed by placing a drop of the solution of penicillin prepared for injection, on the forearm of the patient and giving two scratches with a hypodermic needle through this drop, deep enough to reach the epidermis.

If within 30 minutes, the lines of the scratch develop wheals the patient should be considered hypersensitive to penicillin. If the scratch test is negative, the patient should be tested with 10,000 units and then with 50,000 units injected intradermally.

The radio-allergo-sorbent test (RAST) has also been used to detect hypersensitivity to penicillin and observed to show a good correlation, but it is beyond the scope of this book to describe the test, and it is not available in India for routine testing with penicillin.

Streptomycin: This is a bactericidal drug with a wider range of effectivity. It is effective against staphylococci, streptococci, E. coli, Proteus sp. And Pseudomonas aeruginosa and can be used for infections with staphylococci which are resistant to penicillin.

It is therefore, commonly employed in combination with penicillin where a dose of 0.5 gm of streptomycin is combined with 500,000 units of crystalline penicillin in the same injection. Its main therapeutic value, however, lies in the treatment of tuberculosis and donovanosis where it is used in a dose of 1.0 gm daily by intramuscular injection.

The chief side effects include vertigo and dizziness which are caused by damage to the eighth cranial nerve. Occasionally, the patient may develop hypersensitivity reactions such as urticaria, generalized erythematous rashes or exfoliative dermatitis, and very rarely, the patient may develop renal damage.

Tetracyclines:These are a group of three closely related compounds, viz. chlorotetracycline, oxytetracycline and tetracycline, which are almost interchangeable in so far as their biological properties are concerned, because it is now considered that chlorotetracycline and oxytetracycline owe their therapeutic effect to the parent compound tetracycline.

These act as bacteriostatic agents against a wide range of Gram positive and Gram negative bacteria and are thus called broad spectrum antibiotics, but a large number of bacteria possess the potential of becoming resistant to these antibiotics. These agents can be used orally in a dose of two capsules of 250 gm each, twice a day, but in severe cases, one can use up to two capsules four times a day.

They should not be given with milk because calcium salts of tetracycline are insoluble and thus calcium in the milk interferes with their absorption from the gastro-intestinal tract. These are fairly safe drugs, their chief side effect being indiscripminate killing of gastro-intestinal flora leading to the development of vitamin B complex deficiency and candidiasis of the gastro-intestinal tract.

Occasionally, the patient may also develop urticaria, generalized skin rashes or fixed drug eruptions. When given to children or pregnant women these may get deposited in the developing teeth and produce whitish calcarious streaks on the teeth.

Tetracyclines can also get deposited in the bones of children. Tetracyclines are also nephrotoxic and should be avoided in cases having renal damage.

Demethylchlortetracycline: This is a modification of the original tetracycline which has the same wide range of anti-bacterial activity, but is useful in cases of infections with bacteria which are resistant to other tetracyclines. It is available as 150 mg capsules and is given in a dose of 300 mg twice a day.

Occasionally, patients have been seen to develop photosensitivity due to this drug and therefore, it should be avoided in patients who are sensitive to sunlight.

Chloramphenicol: This is also a broad spectrum antibiotic which acts as a bacteriostatic agent. It is available in 250 mg capsules and can be given in a dose of 500 mg twice a day. The chief side effects include aplastic anaemia, agranulocytosis and thrombocytopaenia which may lead to a fetal termination.

Because of these serious compications, this drug is rarely prescribed. However, its chief utility remains in treating either typhoid or those bacterial infections which are resistant to other antibiotics.

Erythromycin: This is a bactericidal drug which acts by interfering with the protein synthesis by bacterial ribosomes. It is particularly effective against penicillin resistant staphylococci or streptococci and can be given in a dose of 500 mg, twice a day. Apart from giddiness and nephrotoxicity of the estolate salt, it is a fairly safe drug, but organisms can easily develop resistance to this drug.

Ampicillin: This is a modified from of penicillin and is effective against Gram positive as well as Gram negative bacteria. It acts by interfering with the formation of bacterial cell wall. It is usually used in a dose of 500 mg, twice a day but in severe infections the dose can be doubled.

It can be employed in infections where the organisms are resistant to penicillin, but it can be inactivated by penicillinase. Patients who are allergic to penicillin are likely to develop hypersensitivity reactions to ampicillin as well, and therefore, it should be avoided in penicillin sensitive individuals.

Cloxacillin: This is another modification of the original penicillin and is available as 250 mg capsules. It is especially useful against penicillinase-positive staphylococci. It is administered orally and the dose consists of two or three capsules three tiems a day depending upon the severity of infection. Some patients who are allergic to penicillin may develop allergic reaction to cloxacillin as well.

Doxycycline: This is a modification of the original tetracyclines with the advantage that high levels in blood are maintained for prolonged periods. It is available in 100 mg capsules and one capsule a day orally is sufficient.

Like tetracycliens, it has a wide range of anti-bacterial activity, but patients who are allergic-to tetracyclines may develop similar reactions to doxycycline as well. Doxycycline does not damage the kidneys.

Gentamicin: It is specifically effective against Pseudomonas aeruginosa, resistant strains of staphylococci and other organisms. It can be given in a dose of 80 mg intramuscularly at 8 hourly intervals. It should be avoided during pregnancy and given in a smaller dose if there is renal damage. The side effects include dizziness and nephrotoxicity.

Amoxycillin: This is still another modification of penicillin with a broadspectrum of anti-bacterial activity. It is available as 250 mg capsules and the dose consists of one to two capsules thrice a day.

Cephalosporins: These are a group of antibiotics derived from the mould Cephalosporium acremoniu. These have a wide range of anti-bacterial activity against Gram positive and Gram negative organisms, but have no action on Pseudomonas aeruginosa.

Out of the four cephalosporins, cephalexin can be given orally in a dose of 500 mg capsules twice a day whiel cephaloridine is available as 250 or 500 mg ampules an can be given intramuscularly or intravenously in an equivalent dose.

In severe infection, larger doses up to 4 gm a day can be given. The chief side effects include diarrhea, overgrowth of Pseudomonas or Candida in the gastro-intestinal and uro-genital tracts and urticarial eruptions. Nephrotoxicity has also been reported.

Norfloxacin: This belongs to a new group of broad-spectrum bactericidal anti-bacterial agents called fluoroquinolones which are especially active against Pseudomonas aeruginosa and other Gram negative bacteria penicillinase producing gonococci, staphylococci, Salmonella and Shigella.

It is especially useful for urinary tract infections. In acts by inhibiting the synthesis of bacterial DNA. It is given orally in a dose of 400 mg twice a day. It is a very safe drug, the only side effects being gastro-intestinal upsets, drowsiness and dizziness. It may be avoided in children, and pregnant or lactating women.

Ciprofloxacin: This is another antibiotic of quinolone group with a wider range of anti-bacterial activity. It is given orally in a dose of 500 mg twice a day.

Keratolytic Agents In Treatment of Skin Conditions

Medicines employed for promoting desquamation of the scales or thickened stratum corneum are called keratolytic agents.

These are required for the treatment of a large number of diseases such as ichthyosiform dermatoses, palmo-plantar keratodermas, corns, psoriasis and lichenified dermatoses.

These drugs should be avoided in lesions associated with acute or subacute inflammation. The drugs commonly employed for this purpose include the following:

Salicylic acid: It is available as white crystals and can be used only in alcohol or in petrolatum{Petroleum jelly}. It is insoluble in water and leads to break-up of the emulsion if mixed with creams. Nevertheless, water can be added after it has been dissolved in alcohol.

For mild action as in psoriasis, lichenified dermatoses or ichthyosiform dermatoses, a concentration of 3-5% is sufficient, but for severe keratodermas or corns, concentrations as high as 10-40% can be employed.

With higher concentrations, however, there is risk of an irritant reaction especially on delicate skin areas.

Resorcin: It also is a white crystalline substance which can be prescribed in petrolatum base. The concentrations employed for therapeutic effect vary from two to ten percent.

Urea: It is the safest and one of the most effective keratolytic agents. It is soluble in water, glycerine and petrolatum and can be used in concentrations varying from 10 to 40 percent.

Combined with the hygroscopic action of glycerine, it makes a very effective topical therapeutic agent for the treatment of ichthyosiform dermatoses and keratodemas.

Sodium bicarbonate and other alkalis: Sodium hydroxide and potassium hydroxide in concentrated solutions can dissolve keratin within a matter of minutes. A 10 percent solution or more of either of these can be used for removing keratinous layers over the lesion, but a good deal of caution is necessary to avoid undue damage.

A dilute solution (not more than one percent) of these alkalis or a higher concentration i.e. 10 percent of sodium bicarbonate in water can be used for softening the keratin overlying the skin lesions.

Solutions of sodium hydroxide and potassium hydroxide are however unstable, because these absorb carbon dioxide from the air and convert themselves into carbonates.

Astringents And Soothing Application Agents For Skin Conditions

Astringents are agents which when applied on raw areas, react with tissue proteins to form a protective covering on the surface. These thus help in reducing the pain which accompanies such lesions. The commonly used astringents include:

1. Liquor aluminium acetate;
2. Liquor plumbi subacetas; and
3. Silver nitrate.

A one percent aqueous solution of any of these agents can be applied on the raw areas with a cotton soaked with the solution and repeated two or three times in a day.

These agents are unlikely to cause any contact sensitization, but repeated use on extensive areas particularly of lead and silver salts, may lead to sufficient absorption, and systemic toxicity.

SOOTHING APPLICATIONS

An inflamed skin is usually associated with pain, burning or itching. Locally applied agents which relieve these uncomfortable sensations are called soothing applications.

This effect is achieved by the evaporation of the water component. Of the application which produces a cooling effect and vasoconstriction. his effect, however, is temporary and lasts only as long as there is water to evaporate.

An aqueous preparation can act as a soothing application, but calamine lotion and other proprietary medicines with similar constituents are the traditional remedies used for this purpose.

Calamine lotion: This can be prepared by mixing 10 gm each of calamine (zinccarbonate), zinc oxide and glycerine in 100 ml of water. This makes a light pink coloured aqueous suspension which can be applied on the lesions with a piece of cotton or with the fingers.

This is an innocuous preparation with no side effects, but it should not be applied on frankly exuding lesions, because the exudate tends to form a cake with the suspended particles of the calamine lotion which can become troublesome. It should also be avoided on hairy areas.

Cream:Applications of creams on skin lesions also produce a soothing effect because of evaporation of the water phase. These should be preferred for lesions where an emollient action is also required. For exuding lesions, however, creams are contra-indicated.

Talcum: This can also be used as a soothing agent, especially for prickly heat. But talcum should be avoided on exudative areas.

Occlusive Dressing In Local Therapy of Skin Diseases

The main purpose of occlusive dressing is to occlude the area of skin bearing the lesion from the outside atmosphere. Many diseases like intractable lichenified or hyperkeratotic lesions such as those seen in lichen simplex chronicus, hypertrophic lichen planus, psoriasis, keratodermas, etc. are better treated under occlusive dressing with corticosteroids.

The sweat and water released from this area keep on accumulating inside the occluded space, raise its humidity, produce maceration and damage the epidermal barrier. This helps in more efficient penetration of corticosteroids and a quicker regression of the lesion.

Occlusion is done by smearing the lesions liberally with a corticosteroid ointment and covering them with polyethylene sheets or tubing. When the lesions are situated on an extremity, these can be covered with polyethylene tubing and the upper and the lower ends sealed with adhesive tape.

In case a joint is to be enclosed in the occlusive dressing, the polyethylene tubing should be left sufficiently loose to allow free movements of the joint. If the lesions are situated on the trunk, one will have to use polyethylene sheets and seal all the four sides with adhesive tape.

For further protection, the polyethylene dressing may be covered with an ordinary bandage to prevent it from rupturing. This dressing has to be maintained till the humidity inside the occlusion usually takes three or four days, while in summer, even 24 hours may be enough.

When the dressing is removed at the end of this period, there is frequently a good deal of maceration and four smell. This should be washed with soap and water, the skin should be mopped dry and the occlusive dressing repeated after application of more corticosteroid ointment.

This procedure should be continued till the lesions have regressed completely. As a rule, significant improvement can be achieved in two weeks time.

Some patients cannot tolerate the occlusive dressing, because they develop pustular miliaria-like lesions. This happens more frequently in summer months.

In such cases, an ordinary bandage after local application of the corticosteroid ointment, applied after the bath and kept till the next bath, is quite helpful.

Some chemicals such as dimethylsulphoxide (DMSO) have the capacity to overcome the epidermal barrier and thus help the drug to penetrate the skin without resorting to intralesional injections or occlusive dressing.

DMSO is generally added in a concentration of 10-40 percent.

Uses of Bases After Local Medicine In Local Therapy of Skin Conditions

For local application of drugs, the active ingredients have to be dissolved or suspended in a vehicle substance called a base. The main function of the base is to keep the active ingredients in contact with the lesion.

The selection of a base is made depending upon the type and the site of the lesions to be treated and also the solubilities and the reactivities of the active ingredients with the base.

The following bases are commonly used in preparation of medicine for skin condtions:

Water: Sterilized water is a good base for making soothing applications, astringents and anti-infective agents containing dyes. It is an ideal base for treating exuding lesions or those present in the skin folds, because water evaporates easily from the surface, elaving the active ingredients to have their effect on the skin lesion.

Evaporation of water causes cooling and thus has a soothing effect on inflamed lesions.

Glycerine: Glycerine and its analogues such as propylene glycol are viscous fluids with very strong hygroscopic properties. These are, therefore, very good bases for making keratolytic agents and emollients.

These are normally safe, but some subjects experience a transient burning sensation in the skin on application of glycerine. In such cases glycerine should be avoided as a base.

Alcohol: Alcohols are good solvents for some agents such as salicylic acid which are insoluble in water or glycerine. However, after dissolving these in an alcohol these can be added to water or glycerine. Because of their low boiling points, alcohols evaporate very quickly when applied on the skin, producing a cooling effect.

In addition, alcohols have a marked antiseptic effect but when applied on raw areas or ulcers, they produce a severe burning sensation.

Alcohols are  useful as bases particularly for those agents which do not dissolve in water or glycerine and also for preparations which are required to produce a drying effect.

Cream: Two types of creams are available

1. Vanishing creams which are emulsions of oil in water
2. Cold creams which are emulsions of water in oil

Both types of creams have a cooling effect as well as an emollient action on the skin, though vanishing creams have a greater cooling effect while cold creams have a more pronounced emollient action.

Petrolatum: Commonly known as Vaseline, it is a mixture of paraffin hydrocarbons which are soft in consistency at room temperature. It has a pronounced emollient effect and therefore, it is extensively used for making ointments for dry and lichenified lesions. Since it is not miscible with water, it is contra-indicated in exudative and acutely inflamed lesions.

Talcum: It consists of hydrous magnesium polysilicate and is a chemically inert powder. It produces a cooling effect on the skin and also has an absorbent action. It can be mixed with other powdery ingredients and used for prickly heat.

Electro Surgical Procedures For Skin Diseases

Skin lesions such as warts, molluscum contagiosum, skin tags, milia, xanthelasma etc. can be easily treated with electro-surgical procedures. For this purpose, a variety of instruments are available, some of which have an arrangement for electrolysis also.

Basically, there are two types of instruments: (1) unipolar, and (2) bipolar, but both of these work with high intensity AC current. The tissue destruction is caused by the heat generated by the flow of the current through the tissues. The bipolar instruments have a neutral electrode usually made like a flap which is to be placed in contact with the bare skin of the patient.

The other electrode bears a needle at its tip, which is used to destroy the lesion. The unipolar instruments have only the needle electrode. Most apparatuses have a regulator knob which makes it possible to vary the current applied to the needle electrode.

Depending upon the mode of application of the needle electrode to the lesion, one of the following effects can be achieved:

Electro-fulguration: This is produced by a relatively high voltage and low amperage current. The tip of the needle is kept slightly away from the lesion, a spark is generated between the needle and the lesion resulting in destruction of the lesion.

This procedure is useful when only a very superficial destruction is required or if the lesions are of the size of a pin point. Plain warts, small seborrhoeic keratosis and milia may be preferably treated with electro-fulguration.

Electro-desiccation: This is like electro-fulguration, but in this case the needle is kept in contact with the lesion and kept there long enough to bring about drying up and shrinkage of the cells.

This procedure can be employed for small as well as large lesions, but when the lesion is large, the needle will have to be applied at various places on the lesion to achieve complete destruction. It can also be employed to destroy deep seated lesions such as cysts and tumors.

Electro-coagulation: This is produced by a low voltage and high amperage current. The needle electrode is kept on the surface of the lesion and it results in coagulation of the tissue. This procedure is useful for the lesions such as warts, molluscum contagiosum, syringoma, xanthoma, xanthelasma etc. which are located on the skin surface.

Electro-surgical excision: This procedure is employed for the excision of pedunculated lesions lesions such as skin tags, warts, granuloma pyogenicum, etc. irrespective of their size. The lesion is kept pulled away from the skin so as to stretch its pedicle which is repeatedly touched with the needle electrode.

This results in destruction of the pedicle and separation of the lesion from the skin. There is as a rule, very little bleeding during this procedure because the electric current leads to occlusion of the exposed blood vessels as well.

Electro-cautery: It uses a direct current and the electrode gets red hot due to the heat produced by the current. The lesion gets destroyed by the heat of the electrode but electricity does not pass through the tissue. It can be used to destroy superficial lesions or cut through the tissues. The degree of destruction can be controlled under vision.

All these procedures are quite painful and require local anaesthesia which can be achieved by infiltrating one percent lidocaine under the lesion. In case the lesions are very small as in milia, no anaesthesia may be used because the pain of the injection of the anaesthetic is more than the pain produced by the electro-surgical procedure.

All these procedures are quite painful and require local anaesthesia which can be achieved by infiltrating one percent lidocaine under the lesion. In case the lesions are very small as in milia, no anaesthesia may be used because the pain of the injection of the anaesthetic is more than the pain produced by the electro-surgical procedure.

Following the electro-surgical procedure, the tissue which was destroyed dries up into a dark brown crust within 24 hours and falls off in about a week’s time leaving behind a healed area. During this period, it is preferable to keep the area dry for the first one or two days and also apply a local antibiotic ointment twice a day to prevent secondary infection.

Chemo Surgery or Chemical Cauterization of Skin Lesions

Chemosurgery means selective destruction of tissues using chemical agents. Chemsurgical procedures do not require any anaesthesia.it is also termed as chemical cauterization.

Such applications are usually needed

• Chronic ulcers with unhealthy granulation
• Flat warts
• Resistant cases of chloasma
• Papular lesions that do not respond to the conventional treatment.
• Syringoma
• Angiokeratoma

A lot of other lesions are also treated with this.

The cauterizing chemicals commonly used for chemo-surgery include

• Carbolic acid (phenol)
• Trichloroacetic acid
• Strong acid
• Strong alkali

Carbolic acid

It is s available as pinkish crystals which are highly hygroscopic and thus absorb atmospheric moisture to become liquefied. Othrewise, liquiefied phenol can be used as such. It is used in 50, 20 or 10 percent concentration after diluting with water.

Trichloroacetic acid

It is available as whitish crystals which can be dissolved in water to make similar concentrations as those of carbolic acid.

In  large and superficial cauterizations is required, a cotton swab tightly wound over a swab-stick should be dipped in the cauterizing solution, squeezed along the edge of the bottle and painted on the lesion.

Application
It is important to ensure that the cauterizing solution does not get applied on the adjoining normal skin of the patient, his clothes and also the fingers of the treating doctor.

Excess solution can then be mopped with a spirit-soaked swab to stop further action.

Some papular lesions need to be pricked with hypodermic needle to make the procedure effective.

Every time the hypodermic needle is subsequently pricked into the lesion the cauterizing solution flows out and permeates into the surrounding tissue and cauterizes it. Within 24 hours after cauterization, the tissue turns into a brownish black crust which falls off within week’s time after the underlying skin has healed.

It is important to inspect the skin at that time and repeat the cauterization if any part of the lesion has been left behind. In some cases, post-inflammatory hyperpigmentation may follow which however is not permanent.

Chemical cauterization is useful at places where other measures are not available and if used with care it can achieve excellent results.

The major drawback of chemical cauterization is that it is difficult to precisely control the amount of the chemical cauterant applied on the lesion. It can therefore be risky when treating lesions on sensitive areas of skin.

Anti-bacterial agents are used for the treatment of diseases caused by bacterial infections, but these can also be employed to prevent secondary infection in the lesions of other diseases.

There is a large variety of anti-bacterial agents available for topical therapy. While selecting a particular anti-bacterial agent, the patient should be asked if on a previous occasion he developed contact dermatitis to some anti-bacterial agent?

Gentian violent: A rosaniline dye which is soluble in water, it is used as a half to one percent aqueous solution and can be safely applied on exuding or acutely inflamed lesions. It is effective against Gram positive organisms and there is no risk of contact hypersensitivity.

A one percent aqueous solution is very effective against candidiasis as well. The main disadvantage of gentian violet is its deep violet colour which stains the skin and clothes. This colour, however, is not permanent and can be easily washed out.

Brilliant green: This also is a water soluble rosaniline dye which is used as a half to one percent aqueous solution. There are no known instances of bacterial resistance. Contact hypersensitivity is extremely rare.

This dye, however, does not have anti-candida activity.

Acriflavine: This is a yellow coloured dye with anti-bacterial properties, chiefly against Gram positive organisms. Some patients develop contact hypersensitivity to this.

Mercurochrome: It is a red coloured dye used as a one percent aqueous solution in dental practice. It is a relatively weaker anti-bacterial agent, and some instances of contact hypersensitivity to this dye have also been observed.

Zinc oxide: This is a relatively weak anti-bacterial and can be used only in the form of powders or ointments. A 10 to 20 percent concentration in petrolatum base can be used in mildly infective lesions which are not exudative.

A similar concentration in talcum is frequently used for miliaria. This compound is incompatible with salicylic acid and therefore, should not be compounded in the same ointment.

Boric acid: This is also a weak anti-bacterial agent which can be prescribed in petrolatum or talcum base. In 10 to 20 percent concentrations, it is useful in the same conditions, it is useful in the same conditions as indicated for zinc oxide.

Ammoniated mercury: An ointment containing ammoniated mercury in a concentration of one or two percent in petrolatum has been used for non-exudative bacterial infections. When used over large areas for prolonged periods, sufficient amounts have been reported to be absorbed systemically and excreted in the urine.

The incidence of actual systemic toxicity from the mercury absorbed in this manner, however, is quite low. Occasionally, contact dermatitis due to local applications of ammoniated mercury ointment has been observed.

Quinoline compounds: A large number of proprietary medicines containing halogen substituted quinoline compounds are available in the form of ointments containing three or four percent of the active principle.

These agents have moderately good anti-bacterial and antifungal properties and can be recommended when the lesions are non-exudative and associated with mild inflammation. These are also available in combination with corticosteroids.

Nitrofurazone: This agent, present in ‘Furacin’ has a wide spectrum of anti-bacterial activity and is very popular among surgeons and general practitioners. It is available as a 0.2 percent ointment.

But instances of contact hypersensitivity to this drug are so frequent that at present, in India, this is the most frequent contact sensitizer among the topical anti-bacterial agents. It should therefore be avoided.

Sulphonamides: Sulphonamdies can also be used for topical application in the form of ointments or powders, but the incidence of contact hypersensitivity to locally applied sulphonamides is quite high. Therefore, their local use should, preferably, be avoided.

Penicillin: This antibiotic is effective against infections with Gram positive bacteria, but the chances of developing contact hypersensitivity to penicillin are very high. This, it is recommended that topical use of penicillin should be avoided.

Tetracyclines: Tetracycline and its derivatives are all broad spectrum antibiotics active against Gram positive as well as Gram negative bacteria. The incidence of contact dermatitis due to their topical applications is very low.

These are available as proprietary medicines in the form of ointments but since these ointments are made in water-miscible bases, they can be used even on exudative and acutely inflamed lesions. Most of them are available in combination with corticosteroids also, and this combination helps to reduce the severity of the inflammatory reaction.

Chloramphenical: This is also a broad spectrum antibiotic available in the form of an ointment which is fairly safe for topical application. It can be used in the same way as ointments containing tetracyclines.

Neomycin, gramicidin, bacitracin and framycetin (Soframycin): These four antibiotics have a fairly wide spectrum of anti-bacterial activity but can be used for local application only. Several proprietary medicines containing one or more of these antibiotics are available in the form of ointments or powders.

These are also available in combination with corticosteroids and therefore, these have been extensively used. Frequent instances of contact dermatitis due to locally applied neomycin have been reported in western literature, but the incidence in India is relatively lower.

Gentamicin: This is a broad spectrum antibiotic and is particularly useful in infections caused by resistant staphylococci, Pseudomonas aeruginosa and other organisms. These incidences of contact hypersensitivity is low. But it is better to keep these antibiotics in reserve for resistant infections.

Tincture iodine: This is prepared by dissolving 1gm of iodine and 2gm of potassium iodide in 10ml of water and making the volume to 100ml with alcohol. It is a brown coloured liquid with very strong anti-bacterial properties. The alcohol, however, produces a very severe burning sensation when applied on raw areas.

It should also not be applied on delicate skin such as scrotum, groins and axilla. Applications of tincture iodine are specifically recommended on boils and if applied in the early stages it may even abort the lesion. The stains produced by tincture iodine on skin can be cleaned with alcohol, but stains on clothes are permanent.

Povidone iodine: This is an organic iodine preparation claimed to have anti-bacterial and anti-viral properties. Whereas it is a good anti-bacterial agent, its anti-viral activity is not confirmed. In some cases, it has been observed to produce contact dermatitis.

Hexachlorophene and Chloroxylenol (Dettol): These are the two anti-septic agents, with a wide range of anti-bacterial activity. These have been incorporated in toilet soaps and are also used in hospitals for disinfecting skin, surgical instruments and other articles. A few cases of contact dermatitis due to these agents have also been recorded.

Erythromycin and Clindamycin: These are two anti-bacterial agents which have been specifically used for topical applications in acne. It is therefore important to use these only in the form of lotions and not as ointments. c