Scalp Psoriasis in a 13-Year-Old Girl

Case:

This 13-year-old girl, who has just entered secondary school, has been devastated by the appearance of psoriatic plaques on her scalp. She states that her peers shun her and make rude comments about the "scabs" on her face. Her mother has told her not to be concerned, noting that she has lived with extensive psoriasis for nearly 30 years and has had to put up with the loss of her hair. Thus, the patient now not only fears her schoolmates' comments but also worries that she is destined to have severe psoriasis and lose her hair like her mother.

How would you counsel her?

(answer on next page)

Dermclinic–Answer

Scalp involvement does not predict severe psoriasis or hair loss.

The scalp is commonly affected by psoriasis, and scalp psoriasis is often the initial presentation of the disease.

Diagnosis and prognosis of scalp psoriasis. It is often difficult to distinguish between psoriasis and seborrheic dermatitis when the scalp is the only area of involvement; the reason for the difficulty is that both conditions are red and scaly (papulosquamous). Some clinical clues that can help differentiate between the two are:

• Psoriasis typically appears as well demarcated plaques, whereas seborrheic dermatitis most commonly involves the scalp diffusely.

• Thick plaques suggest psoriasis.

• A poor response to simple therapy with shampoos alone suggests psoriasis. 

Scalp involvement does not predict the severity of the psoriasis, nor is it associated with hair loss, unless there is a traumatic or infectious complication. However, the psychological burden of scalp psoriasis is often great because the plaques commonly extend a few centimeters onto the forehead and involve the periauricular areas and the inside of the ear. Moreover, scalp psoriasis is frequently difficult to manage.

Treatment of scalp psoriasis. The treatment of scalp psoriasis provides unique challenges, not the least of which is poor adherence, which in my experience is the most common reason for treatment failure. The facial component of the disease is best managed with topical corticosteroid creams (low to mid potency) or calcineurin inhibitors (see Dermclinic in the October 2008 issue of CONSULTANT FOR PEDIATRICIANS [pages 414-416]). When it comes to treatment of the scalp proper, patients' hair presents challenges: it limits the delivery vehicle for the active agent to substances that patients will find acceptable, and it often limits the timing of treatment to the overnight hours.

In addition, it is extremely difficult for any topical agent to be effective if the scalp plaques are thick and adherent. Thus, I usually first try to remove the scale. This must be done chemically because vigorous physical removal may result in a Koebner phenomenon and worsen the scalp disease. I typically use 3% salicylic acid compounded in an oil base (I prefer a bath oil because these are more easily removed) and applied to the scalp overnight; this is showered out in the morning. After a few applications of salicylic acid, the plaques will be much thinner, allowing for more effective topical therapy.

The treatment of choice, just as with facial psoriasis, is topical corticosteroids. A number of delivery systems are available. Shampoos and foam delivery systems are often preferred because of their ease of use. Topical alcohol solutions can be used in the daytime because they have little noticeable effect on the hair. Overnight oils and creams are less desirable because of the potential messiness.

Vitamin D analogues are also available as alcohol solutions. These can be prescribed for patients who are concerned about using topical corticosteroids.