Itching is a very common occurrence. usually it is harmless but if it occurs persistently, a physician advice should be sought.
Here is the list of few important diseases that can cause itching.
- Allergic dermatitis
- Dry skin
- Drug reaction
- Senile purpura
- Enterobius vermicularis
- Tinea infections
- hydatid cyst
- Diabetes mellitus
- Hepatic diseases
- Obstructive jaundice
- Primary biliary cirrhosis
- Chronic renal failure
- Polycythemia vera
- Hodgkin’s disease
Itching constitutes the most frequent and also the most troublesome symptom in dermatology. Indeed a large number of patients with skin diseases would not seek medical advice, had they not been bothered about the itching which accompanies the skin lesions.
The best way of alleviating itching is the specific treatment of itching, but in case that is not possible, one can at least give symptomatic relief by using one of the following topical drugs:
Chloretone: This compound, also called butyl chloral is an analogue of chloral hydrate and is available as white crystals. It is insoluble in water but can be mixed with cold cream or petrolatum. A concentration of three to five percent is, as a rule, sufficient for producing the antipruritic effect. It is quite safe for local application.
Menthol: This also is a white crystalline substance, which produces a cooling sensation when applied on the skin. A one percent concentration in a cream or a petrolatum base has good anti-pruritic effect, but continued applications may result in an irritant dermatitis.
Camphor: It can be used in a concentration of two to five percent in a cream or a petrolatum base. When applied to the skin it produces a hot sensation and on prolonged usage, this may also result in an irritant dermatitis.
Phenol: It is also called carbolic acid and is available as pinkish crystals. It is a very strong cauterizing agent and therefore, skin and clothes must be protected from the concentrated solution. It is slightly soluble in water but gets liquefied by absorbing moisture from the atmosphere.
Liquefied phenol is used for chemical cauterization of the lesions, but lower concentrations varying from one to five percent can be employed for an anti-pruritic effect.
When applied for prolonged period over large areas, especially for ulcers, sufficient quantities can be absorbed systemically to produce damage to the kidneys. Thus, use of carbolic acid as an anti-pruritic agent should be restricted to only a few applications over small areas.
Crotamiton: Apart from being a potent anti-scabies agent, crotamiton can also be used as an anti-pruritic agent. It is commercially available as a 10 percent lotion or ointment, and is very safe even on prolonged usage on large body areas.
Antihistamines and surface anaesthetics: Antihistamines and surface anaesthetics can produce a mild anaesthesia on the skin. But surface anaesthetics cannot penetrate the intact skin and are therefore, used only on the mucous membranes. Most of the antihistamines on the other hand can penetrate intact skin and produce some anti-pruritic effect.
A few proprietary medicines are available containing antihistaminic drugs in a cream or an aqueous base, but most of the antihistamnes, like surface anaesthetics, are potent contact sensitizers, especially when they are in a cream base.
Therefore, whenever used for prolonged periods, the patient undergoes the risk of developing contact dermatitis. Their use therefore, should be limited to a few applications only. Aqueous solutions of these agents however, have been found to be safe.