Psoriasis is one of the most stubborn skin diseases. It is an inflammatory disease characterised by thick, red, silvery, scaled patches of skin. This disease affects both sexes equally. It may appear at any age but most often at the age ranging from 15 to 30 years. It is, however, rare in infancy and old age. Psoriasis is not contagious.
There are two main types of psoriasis, acute and chronic There are many patients who have chronic psoriatic lesions on the elbows and knees. They suffer from acute outbursts from time to time, when the disease affects large areas of the body. Others have a few chronic lesions at the affected sites and never suffer from severe outbursts. There are many degrees of severity between these two extremes.
It is estimated that between one and four per cent of the world’s population may have visible psoriasis at any one time. There is a higher incidence of this disease among the inhabitants of cold damp countries like Iceland than those of a dry warm climate. The most commonly affected areas are usually those shaded from the sun by hair or clothing. It would thus appear that a psoriatic skin requires an abnormal amount of exposure to sunlight.
Symptoms
Generally, the skin of the person suffering from psoriasis appears red and irritated and may be covered with bright silvery scales. The scales are composed of thin layers of dead abnormal skin cells. Sometimes there is itching. Areas usually involved are elbows, knees, the skin behind the ears, trunk and scalp. It mostly appears first at the back of the elbows and the front of the knees.
The disease may also affect the underarm and genital areas. In some cases, it may be restricted to the scalp, where it is often confused with dandruff. The lesions vary from one or two small localised patches to an extensive spread over the body. Quite often, they are discs from half an inch to several inches in size.
In severe cases, it may disfigure almost the whole body, which can adversely affect the skin’s ability to control the body’s temperature and thereby prove greatly hazardous. The lesions of psoriasis are always dry and rarely become infected.
Causes
The modern medical system has not been able to establish the exact cause of psoriasis. The main cause of the disease appears to be the faulty utilisation of fats. It has been noted that persons with this abnormality have excessive amounts of cholesterol in their skin and blood.
Recent studies have shown that psoriasis involves an abnormality in the mechanism in which the skin grows and replaces itself. This abnormality is related to the metabolism of amino acids, the protein chemicals which are nature’s basic building blocks for the reproduction of cell tissues.
Heredity also plays a role in the development of psoriasis as it tends to occur in families. About 30 per cent of the patients have a family history of the disease. Occasionally it misses a generation and then appears in some members of the next one.
The factors that aggravate or precipitate the outbreak of psoriasis are injury to skin in the form of cuts, burns, minor abrasions, changes in the seasons, defective kidney elimination, infections and the use of certain medicines for the treatment of other diseases. Chronic psoriasis is occasionally linked with deep repressed emotional factors and severity and chronicity of the erruptions depend on the psychological state of the patient.