Common warts are benign epidermal proliferations caused by cutaneous human papillomaviruses (HPV), most often types 1, 2, 4, 27, and 57. They present as hyperkeratotic papules with thrombosed capillaries (“black dots”). Many resolve spontaneously within 1–2 years, but persistence is frequent, especially in older children and adults. Treatments aim to induce local immunity or destroy infected keratinocytes, balancing efficacy with pain, downtime, risk of scarring, and skin type considerations.
Epidemiology and Risk Factors
- Peak in school-age children and adolescents.
- Transmission via skin contact and fomites; microtrauma, maceration, atopic dermatitis increase risk.
- Periungual warts associated with nail-biting/picking.
Clinical Features
- Verruca vulgaris: rough, dome-shaped papules on hands, knees, elbows; pinpoint black dots on paring (thrombosed capillaries).
- Plantar warts: endophytic, tender with walking; callus around lesion.
- Flat warts (verruca plana): smooth, flat-topped 1–3 mm papules on face/dorsal hands/forearms; koebnerization common.
- Filiform warts: thread-like projections on face.
Differential Diagnosis
- Corns/calluses (lack thrombosed capillaries and interrupt skin lines), molluscum, seborrheic keratoses, actinic keratoses, squamous cell carcinoma (particularly in immunosuppressed or chronic solitary lesions).
Diagnosis
- Clinical; dermoscopy shows red/black dots and interrupted skin lines.
- Biopsy if atypical, enlarging, ulcerated, or in immunosuppressed.
Management
- First-line, accessible therapies
- Salicylic acid (SA) 17–40%: nightly application with periodic paring; occlusion improves efficacy; requires weeks–months; low cost and safe for most sites.
- Cryotherapy with liquid nitrogen: 10–30 seconds, 2–3 freeze–thaw cycles every 2–3 weeks; more aggressive for plantar/periungual but balance pain/PIH risk; pretreat with SA/parings.
- Immunomodulatory and adjunctive options
- Candida (or mumps/MMR) antigen intralesional immunotherapy: inject into 1–3 “index” warts every 3–4 weeks × 3–5 sessions; can clear distant warts via immune activation; good for recalcitrant and multiple warts.
- Topical 5-fluorouracil (± SA) for periungual/flat warts under occlusion; monitor for irritation/paronychia.
- Imiquimod 5% for flat warts; evidence mixed; consider in children for facial plana with gentle regimens.
- Tretinoin for flat warts on face.
- Zinc supplementation (oral or topical) may help in deficiency; evidence variable.
- Recalcitrant warts
- Intralesional bleomycin for stubborn plantar/periungual warts; painful; risk of nail dystrophy and Raynaud-like changes—experienced clinicians only.
- Topical contact immunotherapy (SADBE/DPCP) similar to alopecia areata protocols for resistant extensive warts.
- Laser therapies: pulsed dye laser, Nd:YAG, CO2—use for select cases; risk of scarring/PIH; PPE due to plume.
- Hyperthermia/thermotherapy and microneedle RF show emerging evidence.
- Special considerations
- Children: favor painless methods (SA, cantharidin blends, gentle cryo, immunotherapy).
- Skin of color: higher PIH/keloid risk—prefer SA, immunotherapy, conservative cryo; test spots.
- Periungual warts: avoid aggressive cryo/bleomycin that can scar matrix; consider 5-FU/SA under occlusion or immunotherapy.
- Immunosuppressed: more numerous, recalcitrant, and SCC risk; consider reduction of immunosuppression when feasible; aggressive therapies and biopsy of atypical lesions.
- Prevention and counseling
- Do not pick or shave over warts; keep feet dry; wear sandals in communal showers.
- Many warts resolve spontaneously; set expectations for multiple sessions and combined modalities.
References (recent guidelines and key reviews)
- Evidence-based wart management guidelines, 2021–2024.
- RCTs on salicylic acid vs cryotherapy, immunotherapy (Candida antigen), and device therapies, 2021–2024.
- Management of recalcitrant and periungual warts, 2022–2024.