Psoriasis, one of the commonest skin diseases, is also one of the most cosmetically disabling. Although it is very rarely fatal, it produces an immeasurable amount of misery. It affects people mainly at the peak of their working and reproductive lives, and has considerable adverse socio-economic effects on them and their families. The disease has been known for hundreds of years. Many of the diseases referred to in the Bible as leprosy are in fact thought to have been psoriasis.

Psoriasis is a skin condition in which red scaly patches develop on the skin. The areas most commonly affected are the elbows and knees, but the scalp and other areas of the body may also be affected. The main problem with the condition is that it is cosmetically unacceptable, both visually and on account of the scales which are shed from the spots. Fortunately the condition very rarely affects the face, and usually is mainly on areas covered by clothing.

If one parent is affected, it is estimated that there is a 25 per cent chance of immediate members of this family also developing the condition. If two parents are affected, then the likelihood increases to 65 per cent. Fortunately many generations in a family may escape developing the condition.

A number of factors are known to precipitate the onset or appearance of psoriasis. For instance certain infections, such as a streptococcal tonsillitis, are known to be implicated particularly with children. Trauma, due to such things as injuries or sun-burn, may also cause the appearance of psoriasis. It has been suggested that certain hormonal changes such as those occurring with puberty and menopause, may aggravate the condition yet certain other hormonal changes, such as those during pregnancy, may improve the disease. As with many otherconditions. psychological stress can certainly aggravate the disease.

There are various form of psoriasis. There is the acute or Curtate form of the condition, which is usually seen in children and which may be precipitated by tonsillitis.

Then there is the chronic or Plaque form which is the commonest manifestation, and which classically affects the elbows, the knees, the buttocks, and the scalp. In this latter area, it may easily be confused with severe dandruff.

Occasionally psoriasis is confined to the creases or flexures, and sometimes in infancy it occurs as a napkin psoriasis. Here it may be confused with a simple napkin dermatitis or eczema. Nail psoriasis can be most disfiguring. It may affect the nails only or be associated with other forms of psoriasis- Usually it causes lifting of the nail, with or without pitting, and eventually, disintegration. This condition may be misdiagnosed as a fungal infection, from which it must always be separated, as the treatment is very different. Most infrequently, psoriasis takes on a Pustular form, and then is mainly distributed on either the palms or soles, where it has the appearance of an infective process. It is not, however, infective or infectious.

Rarer still, is the exfoliative form of psoriasis, where the entire body skin is shed, and the patient becomes extremely ill. Another of the rare complications of psoriasis is an arthritis, which mainly affects the finger or toe joints, and occasionally the cervical spine, or lower back joints. Psoriasis, however, is not contagious, nor does it affect the blood, or cause cancer.

The basic pathology of psoriasis is related to increased rep rod activity of the cells in the skin and increased production of DNA in the epidermis and dermis. How this comes about is as yet uncertain, although much research work is being done in order to try and elucidate the basic fault, so that hopefully one day it may be corrected. As a result of these abnormalities in the skin there is a marked increase in the rate of cell ‘turnover’. The abnormal cells reproduce approximately ten times more quickly than the normal cells, which results in a build-up of cells which appears as thick scale.

The treatment of such a disfiguring condition is obviously of considerable importance—a society which extols the virtues of physical beauty as much as ours makes people with psoriasis feel very self-conscious. The question is always asked, ‘Can psoriasis be cured?’ Unfortunately it can no more be ‘cured’ than can high blood pressure, schizophrenia, or diabetes. However, and this must be stressed, in most cases it can be completely controlled so that there may be no evidence of the condition at all for long periods of time. Even though the condition may recur, it can once again be brought under complete control.

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