Prurigo pigmentosa

Management Strategy

PP has a distinctive clinical course. Lesions initially start as pruritic, urticarial papules or papulovesicles. The lesions resolve spontaneously within a week, but repetition of the episode results in reticular pigmentation. The pathogenesis of PP remains unknown. Friction from clothing, especially in wet conditions such as sweating or swimming, can trigger the disease. In some cases, ketosis caused by diabetes mellitus, sudden weight loss from a low-carbohydrate diet, or anorexia nervosa precedes PP. Treatment of these conditions can lead to clinical resolution. Several case reports described individuals who developed this condition in association with other disorders, including contact allergic reactions to certain chemical agents, infection with Helicobacter pylori or spirochetes, an atopic diathesis, and pregnancy.

Minocycline (100–200 mg daily) is usually very effective for PP. The effects are mostly observed within 3–7 days after treatment and lead to reductions in itching and papular lesions. Minocycline is regarded as the first-line therapy because it produces fewer adverse reactions, and the remission is reportedly longer than other therapies. Topical or systemic corticosteroids and antihistamines are usually ineffective.