Cutaneous warts
Cutaneous warts (verrucae) are benign hyperkeratotic papules caused by human papillomavirus infecting keratinocytes, most often common (verruca vulgaris), plantar, or flat (verruca plana) warts on the hands, feet, or face. Diagnosis is clinical using the skin-line and black-dot signs, most lesions are self-limited, and troublesome warts are first treated with patient-applied topical salicylic acid 17% or clinician-administered cryotherapy, escalating to cantharidin, podophyllin, laser, or an immune-response agent such as imiquimod for recalcitrant disease.
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What this article covers
- Overview
Definition: cutaneous warts (verrucae) are benign, hyperkeratotic, exophytic papules caused by human papillomavirus (HPV) infection of keratinocytes.
- Epidemiology
Any age, most common in children and young adults: HPV infection causing warts can occur at any age but is typically seen in children and young adults.
- Risk factors
Immunosuppression: immunocompromised patients develop larger, more numerous, and more treatment-resistant warts than immunocompetent patients.
- Pathophysiology
Keratinocyte infection by HPV: warts result from human papillomavirus infecting the epidermis, mucous membranes, and other epithelia, driving localized keratinocyte proliferation.
- Clinical features
Verruca vulgaris (common warts): skin-colored, digitate papules with thrombosed capillaries, most often on the hands, though they can occur anywhere.
- Differential diagnosis
Corn (clavus): thickened stratum corneum over a pressure point, painful, with skin lines retained rather than obscured, unlike a wart, which erases the normal skin creases and hides black dots when pared.
- Diagnosis
Diagnose clinically using the skin-line and black-dot signs: the diagnostic basis is a hyperkeratotic papule that obscures normal skin lines, with paring of the surface revealing thrombosed…
- Management
First, consider no treatment for an asymptomatic, typical wart, since warts are usually self-limited and treatment is often unnecessary.
- Complications
Pigment change or scarring from destructive treatment: cryotherapy, trichloroacetic acid, cantharidin, podophyllin, and laser ablation can each produce pigment change or scarring, particularly depending on the treated location.
- Prognosis
Favorable in immunocompetent patients: most cutaneous warts are self-limited and resolve, with or without treatment, in an immunocompetent host.
- Prevention
HPV vaccination reduces high-risk and genital HPV disease: the HPV vaccine targets subtypes 6, 11, 16, and 18, which together cause 70% of cervical cancer and 90% of genital warts, and vaccination…
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