Viral Warts (Human Papillomavirus Infection)

Overview

Viral warts are benign skin growths caused by infection with human papillomavirus (HPV). Over 200 HPV genotypes have been identified; about 40 of them affect the skin and mucous membranes, producing the common warts seen on hands, feet, genitals, and other sites.

Who it affects: Everyone can develop warts, but they are most common in children and adolescents (ages 5‑20). Adults can also acquire warts, especially when immune function is compromised.

Prevalence: According to the CDC, up to 10‑30% of the general population will develop at least one wart in their lifetime. Genital HPV infection is even more common; the WHO estimates that ≈ 290 million women worldwide are infected with high‑risk HPV types.

Symptoms

Symptoms vary with the type of wart and its location.

Common (cutaneous) warts

• Verruca vulgaris (common wart): Rough, raised, skin‑colored or brown papules, usually on fingers, hands, or knees.
• Verruca plana (flat wart): Smooth, flat-topped lesions 2‑5 mm in diameter, often on the face, neck, or dorsal hands.
• Verruca plantaris (plantar wart): Hard, thickened patches on the soles of the feet; may cause pain when walking.
• Filiform warts: Thread‑like growths that can appear on eyelids, lips, or around the nose.

Genital warts (condyloma acuminata)

• Soft, flesh‑colored or gray growths that may be flat or cauliflower‑like.
• Often appear on the vulva, cervix, penis, scrotum, perianal area, or inside the vagina.
• May cause itching, burning, bleeding after intercourse, or discomfort during urination.

Other possible signs

• Minor pain or tenderness (especially with plantar warts).
• Bleeding if the wart is traumatized.
• Occasional itching or a feeling of a “tickle” under the lesion.

Causes and Risk Factors

HPV infects the basal cells of the epidermis through micro‑abrasions. The virus replicates as the skin cells mature, producing the characteristic wart.

Key causes

• Direct skin‑to‑skin contact with an infected person or contaminated surface.
• Exposure to moist environments (e.g., public swimming pools, communal showers) that facilitate viral survival.

Risk factors

• Age: Children and teens have the highest incidence of cutaneous warts.
• Immunosuppression: HIV, organ transplant recipients, or patients on systemic steroids have higher rates.
• Skin injury: Cuts, scrapes, or calluses provide entry points.
• Frequent hand‑washing or wet work: Increases maceration, weakening skin barrier.
• Sexual activity: Unprotected vaginal, anal, or oral sex raises risk for genital HPV.
• Smoking: Associated with persistence of genital HPV infection.

Diagnosis

Diagnosis is primarily clinical, based on appearance and history. In most cases, no laboratory test is required.

Clinical evaluation

• Physical examination of the lesion(s) – texture, color, location.
• Dermatoscopy can help distinguish warts from other skin tumors.

When testing is needed

• Uncertain diagnosis: A biopsy (punch or shave) may be performed to rule out malignancy.
• Genital warts: Cervical cytology (Pap test) and high‑risk HPV DNA testing are recommended for women; men may undergo HPV PCR testing in research or specialized clinics.
• Immunocompromised patients: Viral typing can guide management.

Treatment Options

Many warts resolve spontaneously within 2 years, especially in children. Treatment is pursued when lesions are painful, cosmetically concerning, or spreading.

Topical medications

• Salicylic acid (20‑40%): First‑line for common and plantar warts; applied daily after soaking.
• Podophyllotoxin: Prescription cream for genital warts; applied twice weekly for up to 4 weeks.
• Imiquimod 5% cream: Immune response modifier that promotes local interferon production; used for genital warts and some cutaneous lesions.
• Tretinoin: Occasionally used to soften warts before removal.

Procedural treatments

• Cryotherapy: Liquid nitrogen applied 10–30 seconds; 1–4 sessions may be needed.
• Electrocautery: Burning warts with electrosurgical current; effective for recalcitrant lesions.
• Laser therapy (CO₂ or pulsed‑dye): Precise ablation for large or resistant warts.
• Surgical excision: Rarely needed but useful for giant warts or when malignancy cannot be excluded.
• Intralesional bleomycin: Injection into wart; reserved for refractory cases.

Systemic therapy

Systemic antivirals are not effective against HPV. However, in patients with extensive genital warts, an oral immunomodulator such as cimetidine has been studied with mixed results.

Lifestyle & self‑care

• Keep warts dry; use foot powder for plantar warts.
• Avoid picking or cutting warts to reduce spread.
• Cover large warts with waterproof dressings during swimming.

Living with Viral Warts (HPV Infection)

Daily management tips

• Hygiene: Wash hands regularly; use separate towels for affected areas.
• Foot care: Wear flip‑flops in public showers; rotate shoes to keep feet dry.
• Skin protection: Apply a thick layer of moisturizer to callused skin before using salicylic acid.
• Monitoring: Photograph lesions periodically to track growth or response to treatment.
• Psychological impact: Warts, especially genital, can cause anxiety. Counseling or support groups are valuable.
• Sexual health: Disclose genital warts to partners, use condoms, and discuss HPV vaccination.

Prevention

• HPV vaccination: The 9‑valent vaccine (Gardasil 9) protects against HPV types 6, 11 (causing most genital warts) and high‑risk types 16, 18, 31, 33, 45, 52, 58. Recommended at ages 9‑14 for both sexes; catch‑up up to age 26 (and sometimes 45) is advised (CDC).
• Hand hygiene: Wash hands after touching potentially contaminated surfaces.
• Protective footwear: Use flip‑flops in communal showers, locker rooms, and pool areas.
• Avoid sharing personal items: Towels, razors, or nail clippers.
• Safe sexual practices: Consistent condom use reduces but does not eliminate genital HPV transmission.
• Skin care: Promptly treat cuts or abrasions; keep skin moisturized to prevent cracking.

Complications

• Secondary bacterial infection: Scratching can introduce bacteria, leading to cellulitis or abscess.
• Painful plantar warts: May interfere with walking or sport activities.
• Psychosocial distress: Particularly with facial or genital warts.
• Malignant transformation: Certain high‑risk HPV types (16, 18) are linked to cervical, anal, penile, and oropharyngeal cancers. Cutaneous warts rarely become cancerous, but chronic lesions in immunosuppressed patients warrant monitoring.
• Recurrence: Even after successful removal, warts can recur if the virus remains dormant in surrounding skin.

When to Seek Emergency Care

References

• Mayo Clinic. “Warts.” https://www.mayoclinic.org
• Centers for Disease Control and Prevention. “HPV Vaccination.” https://www.cdc.gov
• World Health Organization. “Human papillomavirus (HPV) and cervical cancer.” https://www.who.int
• Cleveland Clinic. “Genital Warts Treatment.” https://my.clevelandclinic.org
• National Institutes of Health. “HPV and Skin Warts.” https://www.ncbi.nlm.nih.gov