Plane Warts (Verruca Plana)
Plane warts (verruca plana) appear as slightly elevated, mostly flat, smooth, tan colored papules on face, back of hands, and shin. Their numbers can range from a few lesions to confluent clusters, especially in areas of scratching (a phenomenon called koebnerization). They are common in children and women. They are usually not seen in males after puberty, except in the setting of HIV infection. They are usually caused by HPV-2, 3, or 10. Some cases are associated with HPV types 26-29, 41, and 5 (especially in HIV infections). Many cases regress spontaneously in weeks to months due to cell mediated immunity; some persist for years.