Pityriasis Alba is a common persistent skin disorder. It may affect children of any race, usually in the pre-adolescent years. Pityriasis Alba is self limited. This means it gets well without treatment. It usually disappears in young adulthood. It is a concern only for cosmetic purposes.
The cause of Pityriasis Alba is unknown. The rash appears to get worse when the skin is dry. It is worse in the winter months when it is flakier. It is more noticeable in the summer when the pale skin stands out against a tan.
This rash has patches of lighter skin that can become reddened and itchy. It occurs mainly on the face. The neck, upper chest, and arms may also be involved. Patches may be numerous. They can vary in size from that of a pea to the size of a silver dollar. The borders of the rash are indefinite with the light patches blending gradually into normal skin. Sometimes the rash is covered by very fine skin flakes like a fine dust. This is sometimes confused with tinea versicolor which is due to a fungus.
Your caregiver will often make the diagnosis based on the physical examination. Sometimes skin scrapings are done to make sure a fungus is not present. A biopsy is rarely needed.
Treatment of the rash is usually not needed. It will go away on its own. The rash has no medical consequences. The side effects of medicine may outweigh the cosmetic benefits of treatment.
Moisturizers and steroid (hydrocortisone) creams or ointments may make the patches go away faster. Even with treatment, the rash may take months to resolve. Prolonged treatment with steroid creams or ointments is not usually recommended.
Psoralen plus ultraviolet light (photo-chemotherapy) or PUVA may be used to help with re-pigmentation in extensive cases. This is usually done under the direction of a dermatologist. Recurrence of the rash is high following stopping of light treatment.