Viral Wart (Cutaneous Wart / Verruca)

Warts are benign skin growths caused by the Human Papillomavirus (HPV) and are most common in school-aged children and teenagers. Patients usually present due to cosmetic concern rather than pain, as most warts are asymptomatic.

Symptoms and Distribution:

• Pain: Only typically reported with plantar warts (pain with walking/compression) or periungual warts (may affect nail growth).

• Spread: Warts spread via direct contact or autoinoculation (e.g., scratching spreads plane warts in a line).

• Location: Varies by type (hands, feet, face, knees).

Risk Factors:

• Compromised skin barrier (e.g., eczema, frequent trauma).

• Immunosuppression (HIV, chemotherapy, chronic medications).

• Exposure (e.g., meat handlers, frequent use of communal showers).

Crucial Note for Darker Skin Tones: 

Patients may present later because early inflammation is less visible. Clinicians should inquire about potential painful plantar warts that may have been confused with simple calluses. Patients should be warned that treatment, particularly cryotherapy, carries a high risk of hypopigmentation (light spots) or Post-inflammatory Hyperpigmentation (PIH).

Warts generally present as rough, hyperkeratotic (thickened) papules or plaques. They are diagnosed by the presence of black or red dots (thrombosed capillaries) upon shaving the surface, a key feature distinguishing them from calluses.

Types and Appearance:

• • Common Wart (Verruca Vulgaris): Rough, cauliflower-like surface, typically found on hands, knees, and periungual skin.

  • Plantar Wart (Verruca Plantaris): Deep, often painful, usually on the soles of the feet. They interrupt the normal skin lines (unlike a callus).

  • Plane / Flat Warts: Smooth, flat-topped, and often numerous, appearing on the face, hands, or shins, sometimes spread in lines following shaving.

  • Filiform Warts: Long, thread-like projections, common on the face and eyelids.

Key Examination Nuances in Darker Skin Tones:

• • Warts may appear brown, grey, or charcoal rather than pink.

  • Plane warts may be subtle, blending with the skin tone; look carefully for texture change.

  • Treatment sites, especially from cryotherapy, may show dramatic hypopigmented patches.

  • Mosaic plantar warts may be easily misdiagnosed as simple hyperpigmented calluses.

Treatment is not always necessary as many warts resolve spontaneously (50% in 6 months; 90% in 2 years). The goal is to choose the least painful and least scarring option first.

1. First-line Therapy:

• Topical Salicylic Acid (40%): This is the evidence-based first-line treatment (50–70% cure rate). Requires consistent daily use for 6–12 weeks. This is a good initial option for darker skin tones due to the low risk of pigment change when used correctly.

2. Other Options (Use Cautiously in Darker Skin Tones):

• Cryotherapy (Liquid Nitrogen): Effective but painful, usually applied every 1–2 weeks. Use with caution in darker skin tones due to the high risk of permanent hypopigmentation (lightening).

• Topical Retinoids (Tretinoin): Effective for smooth plane warts.

• Cantharidin: A blistering agent commonly used in paediatric settings.

• Immunotherapy: Reserved for recalcitrant cases (e.g., Intralesional Candida antigen, Diphencyprone) to stimulate a local immune response.

3. Surgical / Procedural Options:
Procedures like curettage + cautery or laser therapy carry a high risk of scarring and PIH in darker skin tones and should be reserved only for highly resistant or severely symptomatic lesions.

4. Observation:
This is a reasonable strategy for children and asymptomatic lesions, as spontaneous resolution avoids treatment-related pigment changes.

NCBI Bookshelf – “Wart” (StatPearls): https://www.ncbi.nlm.nih.gov/books/NBK431047/

DermNet NZ – “Viral wart”: https://dermnetnz.org/topics/viral-wart