Ichthyosis (plural ichthyoses) is a heterogeneous family disorder, mostly comprising of skin disorders of genetic origin. All types of ichthyosis have dry, thickened, scaly or flaky skin like fish.
There are many types of ichthyosis. Important types are being discussed here.
Ichthyosis vulgaris is mildest and most common form accounting for accounts for more than 95% of cases.
Ichthyosis vulgaris is a skin problem that causes dry, dead skin cells to accumulate in patches on the surface of your skin. It is also known as fish scale disease.
It is inherited as an autosomal dominant character and thus, some other member of the family, especially one of the parents at least, should also manifest the disease. The lesions are usually not present at birth, but develop during the first year of life.
These consist of dirty looking, brownish, angulated scales which are present all over the body but are most prominent on the anterior surfaces of the legs. Flexural surfaces of the joints such as the cubital and the popliteal fosae, axillae, groins and other skin folds are as a rule, not involved.
The face and the scalp are also not involved. Some patients in addition, have a diffuse hyperkeratosis of the palms and the soles and occasionally, they may also have small asymptomatic micro-papules around the hair follicles.
The skin as a whole looks very dry. The lesions are worse during winter and improve during the summer months. There is some improvement in the condition at puberty, but otherwise the abnormality persists throughout life. There are no symptoms, but it constitutes a profound cosmetic defect.
The patients generally tend to apply oils, creams, petrolatum and other similar household agents to counter the dryness, but the dryness and the scales continue to bother the patient. Glycerine being a hygroscopic agent, helps in retaining the moisture in the skin and thus, has a better therapeutic effect.
This effect can be further enhanced by the addition of keratolytic agents such as salicylic acid or urea. Fiver percent salicylic acid in petrolatum or 10-40 percent urea in glycerine applied twice a day after the bath has been seen to revert the skin to a normal texture within two to three months.
It is however, necessary to continue these applications for the rest of the life. Urea and glycerine is a safer preparation. To reduce the stickinessof glycerien, a proportionate amount of water may be added to glycerien used for making the solution.
Local applications of retinoic acid and systemic administration of vitamin A is also used in the to reduce hyperkeratosis.
This is an uncommon but severe variant of lamellar Ichthyosis. The child at birth is encased in a thick sheet of hyperkeratosis which shows deep fissure at the folds of skin.
Quite often, this state is not compatible with life and the child dies due to inability to take feeds or due to superadded infection.
Occasionally, however, the child may be able to shed the thick sheets of hyperkeratosis and then manifest the milder form of lamellar Ichthyosis throughout the remaining life.
These cases should be immediately put on systemic corticosteroids giving an equivalent of 10-20 mg of prednisolone a day, preferably by the intramuscular route.
The child should also be treated with prophylactic antibiotics systemically as well as locally. Local applications of emollients may also help in softening the keratotic sheets.
This disease was previously called non-bullous variety of ichthyosiform erythroderma. It is inherited as an autosomal recessive way. Thus consanguine marriages as between close relative, are more likely to result in manifestation of the disease even though other members of the family may be normal.
Usually the affected child shows a diffuse erythema and scaling which is more prominent in the flexural aspects of the joints such as the cubital and the popliteal fossae.
The skin looks shiny and shows fine wrinkles when pressed between the thumb and the index finger. The disease does not show any relationship with the seasons, but becomes less prominent as the age advances.
These cases should be treated with local application of ten percent urea in cold cream or glycerine, but strong keratolytic agents should preferably be avoided especially in the neck, axillae or groins. Intermittent courses with vitamin A giving 50,000 i.u. per day orally for 15 days in a month may also help to some extent.
Severe cases, however, require treatment with corticosteroids in a dose of 10 mg prednisolone a day orally for a few months. For adults, treatment with corticosteroids is usually not required. Some cases have superadded infection with candida, and this should be treated with anti-candida drugs.
This type of ichthyosis is transmitted by means of a recessive gene located on the distal short arm of the X-chromosome.
Thus, the disease is transmitted by females but manifested in the males.
It is based on the deficiency of an enzyme steroid sulphatase in the cultured fibroblasts.
Clinically, the disease resembles ichthyosis vulgaris but the lesions are more profuse and involve a large part of the cubital and the popliteal fossae.
Follicular micro-papules are never seen and hyperkeratosis of the palms and soles does not occur.
The scales may extend even to the face. Comma-shaped corneal opacities developing at the adult stage and cryptorchidism may be associated.
The treatment is same as ichthyosis vulgaris.
Glycerine being a hygroscopic agent, helps in retaining the moisture in the skin. Addition of keratolytic agents such as salicylic acid or urea may enhance the effect.
Five percent salicylic acid in petrolatum or 10-40 percent urea in glycerine applied twice a day after the bath has been seen to revert the skin to a normal texture.
The treatment is life long.
This type of ichthyosis, also known as bullous ichthyosis was earlier known as bullous variety of ichthyosiform erythroderma. Just after birth the child shows bullous lesions and denuded areas with focal areas of hyperkeratosis.
As the child grows the bullous lesions subside, but he develops more hyperkeratosis. The lesions are warty and more pronounced in the flexural folds with secondary infection and foul smell.
An underlying erythroderma in some cases and palmo-plantar keratoderma may also be present. This disease is transmitted as an autosomal dominant trait, but extremely rare.
Histopathologically, the cells of the granular cell layer and the upper part of stratum spinosum develop intracytoplasmic vacuoles, an increased number and size of keratohyaline granules, along with massive hyperkeratosis and a perivascular round cell infiltrate in the upper dermis.
- Local applications of one percent aqueous solutions of gentian violet or brilliant green or any other antibiotic agent.
- For widespread or heavily infected lesions, systemic antibiotics should be used.
Local applications of emollients and keratolytic agents such as five percent salicylic acid in petrolatum or ten to 40 percent urea in glycerine may bring improvement.
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