Common warts (verruca vulgaris) are benign skin growths caused by human papillomavirus infecting the outer skin layer. They spread by direct contact or through small breaks in the skin, are most common in children and often go away on their own within 2 years.
Key symptoms
- Rough, raised, skin-colored bump, usually on the fingers, hands or knees
- Usually painless; tender on pressure points or around the nail
- Can bleed after picking or shaving
- New warts near the first one from scratching or nail biting
What you find on exam
- Firm papule with a rough, cauliflower-like surface
- Tiny black dots from clotted capillaries
- Skin lines pass around the wart, not through it
- Paring the surface shows pinpoint bleeding, which separates it from a callus
Tests
- Clinical diagnosis
- Dermoscopy shows dotted vessels and helps confirm the diagnosis
- Biopsy if atypical, fast-growing or not responding in an older or immunosuppressed patient
Treatment basics
- Watchful waiting is reasonable, since many clear by themselves
- Topical salicylic acid daily after soaking and filing the wart
- Cryotherapy with liquid nitrogen every 2 to 3 weeks
- Resistant warts: cantharidin, imiquimod, intralesional immunotherapy or laser
Red flags
- Bleeding, ulcerated or fast-growing lesion in an adult (consider skin cancer)
- Many widespread or very stubborn warts (look for immunosuppression)
- Wart under the nail that damages the nail
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; AAMC Core Entrustable Professional Activities (Core EPAs). Written by Making Synapses. Making Synapses is not affiliated with these organizations.