Psoriasis: Scalp

Psoriasis of the scalp is a chronic form of psoriasis which affects the scalp, typically on the back of the head, though other areas and even the entire head may become involved in some cases. The condition consists of two subtypes with distinct presentations. Sebopsoriasis is in actually a combination of psoriasis and seborrhoeic dermatitis, which presents as yellow, greasy scaling and may affect the chest and face in addition to the scalp. Pityriasis amiantacea presents as thicker, yellow-white scales, which tend to stick to hairs as they grow and underlying skin may be red and scaly or appear normal. While it typically affects only one area of the scalp, it may involve the entire scalp in rare cases, and localized hair loss is common and typically regrows after treatment.This subtype may appear ideopathically, or in association with psoriasis of the skin, lichen simplex, or seborrhoeic dermatitis. Both subtypes may be accompanied by itching, and may be vulnerable to secondary infection.

The exact cause of all types of psoriasis, including flexural psoriasis, is unknown, though it is thought to be caused by functional errors in the immune system. The condition affects men and women equally, though often women will show signs at an earlier age.

Differential Diagnosis (Other conditions with similar appearance)
Pityriasis rubra pilaris
Secondary Syphilis
Parapsoriasis
Lichen simplex

Psoriasis of the scalp is generally diagnosed based on appearance of the affected area. A skin biopsy may be performed to rule out similar appearing conditions.