Scalp and hair care in psoriasis

The scalp, like elbows, knees and lower back, is a classic site for the common type of psoriasis.

How is scalp psoriasis diagnosed?
Some patients have severe scaling and itching, though the majority experience varying discomfort, eg. dryness, tightness or soreness. Sometimes patients experience thinning of the hair around the affected site.

Diagnosis is usually easy. Multiple red patches with sharp margins and prominent "silvery" scales are quite characteristic. Sometimes severe dandruff, a scaly type of eczema and scalp fungal infection may appear similar to the untrained eye, but these can easily be excluded by medical assessment and investigation.

How is scalp psoriasis treated?
Treatment principles are the same as for psoriasis in general, ie. either slowing the fast "turnover" of affected skin with tars, dithranol or topical corticosteroids, or simply treating the effects of this by dissolving or removing scales, eg. with salicylic acid or shampoos. In practice many remedies are "cocktails" containing different strengths of several ingredients.

Any do's and don’ts for treating scalp psoriasis?

• Greasy ointments should not be used on the hairy scalp. They make a matted greasy mess of the hair, look awful and are very difficult to wash out even with strong detergent shampoos. Whatever the active ingredient, scalp treatments are best applied in a liquid cream or pomade base. The type actually used will depend on the kind of psoriasis, the preference of the GP or dermatologist and, last but by no means least, the judgment of the patient.
• It is important to treat the scalp and not the hair. By making front to back parting, then repeating the process from side to side, all the affected areas can be reached. In this way even with a messy pomade, the hair remains respectable. This mode of application is often called the "chessboard method", as the treatment is applied as if along the chessboard lines.
• Dithranol is often said to be contra-indicated on the scalp because of its dyeing effect on hair. This is a half truth. Light haired patients should probably not use dithranol since staining of hair may be unacceptably obvious, even though only temporary.
• In general the scalp tolerates topical corticosteroid (cortisone) preparations better than most other parts of the body. Doctors are using increasing amounts as the rarity of side effects on the scalp becomes more widely known, ie. such things as thinning of skin, bruising, proneness to infection and poor healing are less likely to occur. From scalp application alone there is no chance of significant absorption into the body. It is routine medical practice to use cortisone preparations as infrequently and for as short a time as possible, ie. twice per day initially and slowly decreasing to once or twice weekly, after improvement has occurred. If no obvious benefit accrues within three to four weeks they should be stopped immediately.
• Because of natural variation, psoriasis on the scalp can be expected to return to normal for some of the time. Tar and dithranol preparations, if persisted with, can be expected to accentuate this and give periods of freedom from treatment. Topical cortisones, though more acceptable cosmetically, in general are more likely to be needed regularly; because of their biological action, they can cause worsening ('rebound') of psoriasis if stopped suddenly.

Can I style my hair as normal?
Hair in psoriasis is essentially normal and can withstand cosmetic procedures without special precautions. Scalp psoriasis is not therefore a reason for stopping shampooing, setting, bleaching, perming, etc. though demands of treatment will limit their use somewhat. Combing is often not only good but a necessity if scaling is thick because severe psoriasis is often associated with the occurrence of hair casts which can be removed by frequent combing since they slide off like a ring off a finger. In practice, the advice here is that, if dandruff on hair is severe, then frequent combing and brushing may help as much as treatment. Care should, however, be taken to avoid excessively scratching the scalp itself.

Treating scalp psoriasis is time-consuming but it is time well spent.