Snapshot A 6-year-old girl presents to the pediatric dermatologist’s office for multiple warts on her hands and feet. She reports that they are not physically painful or itchy, but they are embarrassing. Her friends avoid touching her because of the warts. Her past medical history includes atopic dermatitis. On physical exam, she has multiple 4-5 mm flesh-colored papules. Because of the associated stigma at school, the pediatrician suggests using topical salicylic acid to treat these lesions. Introduction Clinical definition cutaneous warts, or verrucae, are skin lesions caused by infection with human papillomaviruses (HPVs) common forms common warts (verruca vulgaris) flat warts (verruca plana) HPV type 3 and 10 plantar warts (verruca plantaris) HPV type 1 anogenital warts also known as condylomata acuminata HPV type 6 and 11 Epidemiology demographics children and young adults risk factors atopic dermatitis immunosuppression walking barefoot in communal swimming areas occupations handlers of meat and fish Etiology HPVs over 150 subtypes Pathogenesis transmitted through contact with infected skin of mucous membranes warts contain high viral load virus invades epidermal basal layer through microabrasions and are confined to epidermis incubation period is 2-6 months Prognosis often spontaneously resolves in children often require several sessions of treatment in adults Presentation Symptoms asymptomatic commonly appear at sites of trauma Physical exam common warts flesh-colored papules can be cauliflower-shaped or smooth black dots, which are thrombosed capillaries, appear when pared with a surgical blade hands are most commonly involved flat warts pink, light brown, or light yellow flat-topped papules most commonly on mouth and forehead plantar warts on plantar surface of feet, often at points of maximum pressure accompanied with thick callus single or grouped lesions warts on adjacent toes “kissing lesions” Studies Biopsy indications if diagnosis is unclear Histology epidermal hyperplasia hyperkeratosis koilocytosis Diagnostic criteria a clinical diagnosis Differential Seborrheic keratosis “stuck on” appearance Acrochordon (skin tags) pedunculated Treatment Medical destruction of warts indications cosmetic reasons associated pain or irritation immunosuppression modalities topical salicylic acid first-line cryotherapy because of pain, it usually used in older children or adults topical cantharidin laser topical immunotherapy indications refractory to first-line treatment modalities squaric acid dibutylester dinitrochlorobenzene (DNCB) diphenylcyclopropenone (DPCP) Complications No significant complications