Flat Warts (Verruca Plana)

June 19, 2012

The “rash” of innumerable asymptomatic flat-topped papules on this teenager’s face is highly likely to be flat warts.

A 17-year-old girl presents for evaluation of a facial “rash” consisting of innumerable, asymptomatic, 1- to 3-mm flat-topped papules.

Key point: Based on lesion morphology and location, as well as the young age of the patient, this is highly likely to be flat warts. The differential diagnosis includes acne comedones, lichen nitidus, lichen planus, and papular cutaneous sarcoid. A single lesion was removed by sharp curettage for histologic examination to verify the diagnosis of verruca plana.

Treatment: Flat warts may be very difficult to eradicate. Topical application of one or more of the following may prove beneficial:

• Salicylic acid 10%
• Topical 5-fluorouracil 5%
• Imiquimod 3.75% or 5%
• Glycolic acid 10% to 30%
• Tretinoin 0.025% to 0.05%
• Light liquid nitrogen cryospray

Note: Exercise caution not to perform any treatment that will result in permanent scarring.