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.
Try two board-style Verrucae questions
Real questions from the FirstPassPA bank, with the full explanation. Pick an answer — no signup, no email.
Question 1DermatologyEasy
A 9-year-old boy is seen for several common warts on his hands present for 8 months. He is otherwise healthy. Exam shows three hyperkeratotic papules on the dorsum of the right hand, one with surrounding skin maceration after a recent attempt at home cryotherapy. There is no fever, lymphadenopathy, or surrounding cellulitis. The lesions are otherwise typical verrucae vulgares. Which of the following is the most likely complication of these lesions?
AAutoinoculation and local spread
BScarring after spontaneous regression
CSquamous cell carcinoma
DLifelong persistence of the warts
EPermanent loss of fingernail growth
Reveal answer & full explanation
Correct answer: A — Autoinoculation and local spread
AAutoinoculation and local spread✓
BScarring after spontaneous regression
CSquamous cell carcinoma
DLifelong persistence of the warts
EPermanent loss of fingernail growth
Why Autoinoculation and local spread is correct
Verruca vulgaris is a benign epidermal infection caused by cutaneous HPV strains, most often HPV 1, 2, and 4.
The great majority of lesions are self-limited and resolve over 1–2 years.
The most common clinically relevant complication is autoinoculation, in which virus is transferred by scratching, shaving, nail biting, or trauma to adjacent or distant skin, producing new lesions in a linear or clustered distribution.
Periungual and subungual spread is particularly common in nail biters; warts may also spread to family members via shared towels or shower floors.
Why the others are wrong
Permanent loss of fingernail growth — rare; periungual warts may temporarily distort the nail plate, but matrix destruction with permanent anonychia is not characteristic.
Scarring after spontaneous regression — HPV infection is confined to the epidermis, so warts that regress on their own heal without a scar; scarring follows destructive treatment such as aggressive cryotherapy, electrosurgery, or excision, not the natural course of the lesion.
Squamous cell carcinoma — associated with high-risk mucosal HPV types (16, 18) in anogenital and oropharyngeal sites, not with cutaneous HPV 1/2/4 in common hand warts in immunocompetent children.
Lifelong persistence of the warts — tempting because these warts have lasted 8 months and a home freezing attempt failed, but in an otherwise healthy child most common warts regress spontaneously over 1–2 years as cell-mediated immunity clears the virus, so indefinite persistence is not the expected course.
Additional high-yield points
The absence of fever, lymphadenopathy, and cellulitis shows the macerated lesion is not secondarily infected; cutaneous HPV does not cause viremia or systemic illness.
Question 2DermatologyMedium
A 12-year-old boy is brought to clinic for evaluation of bumps on his hands that have been present for 4 months. The lesions are asymptomatic but he is embarrassed about them at school. He denies trauma, fever, or systemic symptoms. Exam reveals several 3-6 mm firm, hyperkeratotic, skin-colored papules on the dorsa of both hands and one finger. Paring of the surface with a #15 blade reveals pinpoint black dots and small bleeding points; normal dermatoglyphic skin lines are interrupted over the lesions. Which of the following is the most likely diagnosis?
ASeborrheic keratosis
BAcrochordon
CMolluscum contagiosum
DGranuloma annulare
EVerruca vulgaris
Reveal answer & full explanation
Correct answer: E — Verruca vulgaris
ASeborrheic keratosis
BAcrochordon
CMolluscum contagiosum
DGranuloma annulare
EVerruca vulgaris✓
Why verruca vulgaris is correct
Verruca vulgaris (common wart) is a benign epidermal proliferation caused by human papillomavirus, most often HPV types 1, 2, and 4.
It is the most common viral skin infection in children and presents as firm, hyperkeratotic, skin-colored papules with a rough, cauliflower-like surface, most often on the hands, fingers, and knees.
Two classic clinical clues: interruption of the normal skin lines (dermatoglyphics) coursing over the lesion, and pinpoint black dots after paring, which represent thrombosed dermal capillaries within elongated dermal papillae.
Diagnosis is clinical; biopsy is rarely needed.
Why the others are wrong
Molluscum contagiosum — caused by a poxvirus; produces smooth, dome-shaped, pearly papules with central umbilication, not hyperkeratotic surfaces, and lacks black dots on paring.
Seborrheic keratosis — presents as a 'stuck-on,' waxy, sharply demarcated plaque most often in adults over 40 and is uncommon in children.
Acrochordon (skin tag) — a soft, pedunculated, flesh-colored papule found in skin folds such as the neck and axillae, not on the dorsal hands, and lacks hyperkeratosis.
Granuloma annulare — a common cause of asymptomatic skin-colored papules on the dorsal hands and fingers of children, which makes it tempting here; however, it is a dermal granulomatous process beneath a normal epidermis, so its papules are smooth and often coalesce into annular plaques, without hyperkeratosis or black dots on paring.
That's 2. Get 7,700+ more.
Unlock the full FirstPassPA bank: 7,700+ board-style questions, flashcards, and an AI tutor that explains every answer. Your 7-day free trial includes everything, and there's no credit card required.
You've read your 2 free diagnosis previews. Create your free account to unlock the full Verrucae (Warts, HPV) outline — plus all 514 diagnoses, 7,700+ board-style questions, flashcards, and an AI tutor. Your 7-day free trial includes everything, and there's no credit card required.
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.
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
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
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 2018: cytology q3y ages 21-29; cytology+HPV co-testing q5y OR cytology q3y OR primary HPV testing q5y ages 30-65 (ACOG 2026 prefers clinician-collected primary HPV testing q5y at 30-65 for average risk)
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)
AVOID podofilox, podophyllin, and sinecatechins (should not be used in pregnancy per CDC 2021); avoid imiquimod (appears low risk but data are insufficient) and 5-FU
Cesarean delivery is NOT indicated solely to prevent HPV transmission to the newborn; reserve it for warts that obstruct the pelvic outlet or would cause excessive bleeding with vaginal delivery (CDC 2021)
Immunocompromised
More refractory and recurrent; multimodal therapy; surveillance for SCC transformation
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 (rare) in infants of mothers with anogenital warts (HPV 6/11); it is unclear whether cesarean delivery prevents it
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.
ACIP 2019 — Human Papillomavirus Vaccination for Adults: Updated Recommendations of the Advisory Committee on Immunization Practices (Meites et al., MMWR 2019)
AFP 2011 — Mulhem E, Pinelis S. Treatment of nongenital cutaneous warts. Am Fam Physician 2011;84(3):288-293
USPSTF 2018 — USPSTF Recommendation: Screening for Cervical Cancer (JAMA 2018)
Practice Dermatology questions on FirstPassPA
Turn this outline into retention. 7,700+ board-style questions with an AI tutor that explains every answer — free to start, no card required.
Educational use only. This outline is a study aid for PA students and is not medical advice or a substitute for clinical judgment. FirstPassPA is an independent study tool and is not affiliated with, endorsed by, or sponsored by NCCPA or PAEA. PANCE® and PANRE® are registered trademarks of the National Commission on Certification of Physician Assistants; End of Rotation™ is a program of the Physician Assistant Education Association.