Overview
Warts are non-cancerous skin growths caused by the human papillomavirus (HPV). Different HPV types cause warts on different body parts: common warts on hands, plantar warts on feet, flat warts on face and hands, and genital warts (covered separately under STIs). Warts are contagious but most are harmless and many resolve without treatment over time.
How common is it?
Warts affect approximately 10 to 12% of people at any given time, with higher prevalence in children and young adults. Up to 20% of school-age children have warts at some point.
Causes and risk factors
HPV infects the outer layer of skin through tiny cuts or breaks, causing excessive keratinocyte proliferation producing the characteristic rough growth.
Common risk factors
- Direct skin contact with an infected person
- Touching contaminated surfaces: gym floors, swimming pools, changing rooms
- Skin cuts or breaks providing virus entry points
- Nail biting (spreads warts around nail folds)
- Immunosuppression (warts are more extensive and harder to treat)
- Children and young adults (higher skin-to-skin contact, evolving immune response)
Symptoms
- Rough, skin-coloured, raised bumps (common warts) on hands or fingers
- Plantar warts (verrucae): flat or slightly raised, on the sole of the foot, with characteristic black dots (thrombosed capillaries), often painful when walking
- Flat warts: smoother, smaller, and lighter in colour, on face and hands
- Warts may appear in clusters
- Most warts are painless except plantar warts
When to see a doctor
See a GP for warts that are painful, multiplying rapidly, on the face or genitals, not responding to over-the-counter treatment, or if you are immunosuppressed. Diabetic foot warts need specialist care.
Diagnosis
Clinical diagnosis. Dermoscopy shows characteristic vascular pattern (dotted vessels). Biopsy for uncertain or atypical lesions.
Treatments
Watchful waiting
Two-thirds of common warts in children resolve spontaneously within 2 years. Observation without treatment is a reasonable choice, particularly in young children.
Salicylic acid preparations
Applied daily after filing and soaking the wart. Concentrations of 12 to 26% for common warts; higher for plantar warts. Takes weeks to months. First-line OTC treatment.
Cryotherapy
Liquid nitrogen applied in clinic freezes and destroys wart tissue. Repeated every 2 to 3 weeks. Effective in about 70% after multiple treatments. Painful — may be poorly tolerated in young children.
Surgical removal and laser
Curettage, electrocautery, or CO2 laser for warts resistant to other treatments. Leaves scar. Carbon dioxide laser for resistant plantar warts and immunocompromised patients.
Self-care and lifestyle
- Cover verrucae (plantar warts) with a waterproof plaster when swimming
- Wear flip-flops in communal changing areas
- Do not pick or scratch warts as this spreads HPV to other skin areas
- File warts gently before applying salicylic acid to remove surface keratin
Prevention
HPV vaccination (Gardasil 9) protects against the HPV types most likely to cause genital warts and high-risk types. No specific prevention for common warts, but avoiding barefoot contact in communal areas reduces verruca risk.