Dermatology · PANCE / PANRE

Verrucae (Warts, HPV)

Benign epidermal proliferations caused by human papillomavirus (HPV); morphology varies by anatomic site and HPV type.

Also known as: warts, verruca vulgaris, common wart, plantar wart, flat wart, condyloma acuminatum, genital warts, HPV

Overview

Benign epidermal proliferations caused by infection of keratinocytes by human papillomavirus (HPV). Clinical variants include common warts (verruca vulgaris), plantar warts (verruca plantaris), flat warts (verruca plana), filiform, periungual, and anogenital warts (condyloma acuminatum).

Epidemiology

Cutaneous warts affect ~10% of children and young adults. Genital HPV is the most common STI worldwide — ~80% lifetime prevalence in sexually active adults. Most infections clear spontaneously within 1-2 years.

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Risk factors

Cutaneous: skin trauma, communal showers/pools (plantar warts), nail biting, immunosuppression, atopic dermatitis
Anogenital: sexual activity, multiple partners, immunosuppression (HIV, transplant), smoking, lack of HPV vaccination
HPV types: low-risk cutaneous (HPV 1, 2, 4, 27, 57), low-risk anogenital (HPV 6, 11 — 90% of warts), high-risk oncogenic (HPV 16, 18, 31, 33, 45, 52, 58 — cervical and other cancers)

Pathophysiology

HPV infects basal keratinocytes through microabrasions; viral DNA replicates as keratinocytes differentiate. Productive infection produces hyperkeratosis, acanthosis, papillomatosis, and koilocytes (vacuolated cells with raisin-like nuclei). High-risk types integrate into host DNA, expressing E6/E7 oncoproteins that inactivate p53 and Rb → dysplasia and carcinoma over years to decades.

Clinical presentation

Symptoms

Asymptomatic in most cases; cosmetic concern
Plantar warts can be painful with weight-bearing
Anogenital warts: itching, bleeding, dyspareunia, anxiety; rarely painful unless secondary infection

Signs / physical exam

Verruca vulgaris (common wart): hyperkeratotic flesh-colored papule with rough verrucous surface and pinpoint black dots (thrombosed capillaries); hands, fingers, knees; disrupts skin lines (dermatoglyphics)
Plantar warts: endophytic (inward-growing) hyperkeratotic plaques on weight-bearing surfaces; painful with lateral compression; mosaic warts = coalesced cluster
Flat warts (verruca plana): small (1-5 mm) smooth flat-topped flesh-colored papules; face, dorsal hands, shins; spread linearly by autoinoculation (Koebner phenomenon)
Filiform warts: thin finger-like projections; face, eyelids, lips, neck
Periungual warts: around nail folds; nail biters; can cause nail dystrophy
Condyloma acuminatum (anogenital): pink to flesh-colored soft cauliflower-like papules and plaques on vulva, vagina, cervix, perianal area, penis, anal canal; can form large confluent masses (Buschke-Löwenstein tumor)
Bowenoid papulosis: pigmented well-demarcated papules on genitalia, SCC in situ histology

Classic findings

Verrucous papule with pinpoint black dots (thrombosed capillaries) that disrupts normal skin lines.

Differential diagnosis

Molluscum contagiosum — Smooth dome-shaped umbilicated papules; central core; poxvirus, not HPV
Seborrheic keratosis — 'Stuck-on' waxy plaques in older adults; not viral
Corn / callus (plantar wart DDx) — No skin lines disrupted, no thrombosed capillaries; paring reveals translucent keratin (vs black dots of wart)
Acrochordon (skin tag) — Pedunculated, neck/axilla, not verrucous surface
Squamous cell carcinoma — Hyperkeratotic ulcerated lesion in sun-exposed area; chronic, non-healing; biopsy
Lichen planus — Violaceous polygonal flat papules with Wickham striae
Condyloma lata (secondary syphilis) — Moist, flat-topped papules in anogenital region; RPR positive
Bowenoid papulosis — Pigmented genital papules with SCC in situ histology; HPV 16-related

Diagnostic workup

Diagnostic criteria

Clinical morphology + paring findings; biopsy for atypical lesions.

Labs

Clinical diagnosis usually sufficient
Paring of suspected plantar wart reveals thrombosed capillaries (corn does not)
Biopsy for atypical, refractory, or suspicious lesions (rule out SCC, especially in immunosuppressed or older patients)
Acetic acid application (3-5%) for anogenital evaluation — whitens HPV-infected skin (sensitive but not specific)
HPV PCR/typing in research/cervical screening contexts; cervical cytology (Pap smear) per USPSTF screening guidelines
Anal cytology for HIV-positive MSM (consider)

Imaging

Not indicated for typical warts

Diagnostic algorithm

Variant	Site / Appearance	First-Line Therapy
Verruca vulgaris	Hands/knees — verrucous papule with black dots	Salicylic acid 17-40% + cryotherapy
Plantar wart	Weight-bearing foot — endophytic hyperkeratotic plaque	Paring + salicylic acid; cryotherapy; avoid aggressive excision
Flat wart (verruca plana)	Face/dorsal hands — small flat-topped papules	Tretinoin, imiquimod, 5-FU
Filiform	Face/neck — finger-like projections	Snip excision or cryotherapy
Condyloma acuminatum	Anogenital — soft cauliflower papules	Patient: imiquimod / podofilox; Provider: cryotherapy / TCA / excision
Prevention	All HPV-related disease	9-valent HPV vaccine routine age 11-12, catch-up to 26

Verrucae variants, anatomic distribution, and first-line therapy.

Treatment

First-line

Cutaneous warts (common, plantar, periungual): salicylic acid 17-40% topical daily after soaking and paring × 6-12 weeks (most cost-effective; first-line in pediatrics); cryotherapy (liquid nitrogen) every 2-3 weeks for 3-6 sessions
Flat warts: tretinoin cream, imiquimod 5% cream, or 5-fluorouracil cream (gentler, fewer cosmetic sequelae)
Anogenital warts (patient-applied): imiquimod 5% cream 3x/week × up to 16 weeks (immunomodulator); podofilox 0.5% solution/gel BID × 3 days then off × 4 days, up to 4 cycles; sinecatechins 15% ointment TID
Anogenital warts (provider-administered): cryotherapy, trichloroacetic acid (TCA) 80-90%, surgical excision, electrocautery, laser ablation, podophyllin resin 10-25%
HPV VACCINATION (PRIMARY PREVENTION): 9-valent HPV vaccine (Gardasil 9) — routinely at age 11-12 (can start at 9); catch-up through age 26; shared decision through age 45 (CDC ACIP)
Cervical cancer screening per USPSTF/ACOG: cytology q3y ages 21-29; cytology+HPV co-testing q5y OR cytology q3y OR primary HPV testing q5y ages 30-65

Recalcitrant cutaneous warts

Intralesional candida or mumps antigen immunotherapy
Intralesional bleomycin or 5-fluorouracil
Pulsed dye laser, CO2 laser
Topical cantharidin 0.7% in office (especially pediatric)
Cimetidine 30-40 mg/kg/day off-label (mixed evidence)

Pregnancy

TCA, cryotherapy, surgical removal are safe
AVOID imiquimod, podofilox, podophyllin, 5-FU (teratogenic or untested)

Immunocompromised

More refractory and recurrent; multimodal therapy; surveillance for SCC transformation
Optimize underlying immune status

Second-line / adjunct

Duct tape occlusion (gentle keratolysis; limited evidence)
Counsel: most warts resolve spontaneously within 2 years in immunocompetent hosts
Avoid surgical destruction of plantar warts due to risk of painful scar

Complications

Painful gait alteration from plantar warts
Spread by autoinoculation (Koebner phenomenon)
Cosmetic and psychosocial impact
Cervical, anal, oropharyngeal, vulvar, vaginal, penile cancer from high-risk HPV (long latency 10-30 years)
Recurrent respiratory papillomatosis in infants born vaginally to mothers with active condyloma
Scarring from aggressive destructive therapies
Bowenoid papulosis → in situ SCC progression risk

PANCE pearls

Paring a plantar wart reveals thrombosed capillaries (pinpoint black dots) and disrupts the normal skin lines — a corn does neither.
Most warts resolve spontaneously within 1-2 years; aggressive treatment is not always necessary, especially in children.
Imiquimod and podofilox are PATIENT-APPLIED for anogenital warts; cryotherapy, TCA, and excision are PROVIDER-APPLIED.
HPV vaccination is most effective BEFORE sexual debut; routine at age 11-12, catch-up to 26, shared decision to 45.
A persistent, ulcerated, or bleeding 'wart' in a sun-exposed area of an older adult is squamous cell carcinoma until biopsied.

References

CDC STI 2021 — CDC Sexually Transmitted Infections Treatment Guidelines, 2021 — Anogenital Warts (Workowski et al., MMWR Recomm Rep 2021)
ACIP 2019 — Human Papillomavirus Vaccination for Adults: Updated Recommendations of the Advisory Committee on Immunization Practices (Meites et al., MMWR 2019)
AAD 2024 — Management of Nongenital Cutaneous Warts (AAD review series)
USPSTF 2018 — USPSTF Recommendation: Screening for Cervical Cancer (JAMA 2018)

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