A reader had always assumed that her husband's dandruff was inevitable and recommended Nizoral, a medicated shampoo. Recently he joined a firm of City solicitors and is now expected to wear a dark suit. The dandruff that didn't show on the clothes she had chosen carefully for him is now unsightly. Her husband's doctor has told him that he doesn't have ordinary dandruff, but a scaly scalp as the result of psoriasis. Any advice?

Scalp psoriasis is often mistaken for either ordinary dandruff or seborrhoeic dermatitis. Half of all psoriasis patients suffer from scalp psoriasis, as the scalp is the first (and sometimes only) area to be affected. This produces red, itchy, scaly plaques that may extend beyond the scalp, showing as an inflamed margin between the forehead and the hairline.

Dermatologists who see the worst cases warn patients that scalp psoriasis is one of the more difficult forms of the condition to treat effectively. That said, most people can be helped and I'm sure your husband's suit will soon be as smart as those of his colleagues.

Unfortunately, tension and stress tends to cause flare-ups of psoriasis. Perhaps your husband's new job has been a factor. Some patients also notice a relationship to the weather: scalp psoriasis may be worse in hot, humid conditions, possibly because this encourages an overgrowth of scalp yeasts. Unlike other forms of the condition, scalp psoriasis does not usually benefit from sunlight, possibly because of the sweating caused.

Nizoral shampoo helps in cases of scalp psoriasis because it reduces any intercurrent yeast infections. Specific treatments for scalp psoriasis include Betnovate, Dermovate and Dovonex scalp applications or lotions.

Recently, clobetasol propionate, a topical steroid, has been made into Etrivex shampoo. This is a prescription-only shampoo to be used only on the scalp - it should be kept away from the eyes, face and other areas of soft skin.

It should be used according to the recommendations of the patient's doctor and the advice contained in the detailed guide that accompanies the shampoo.