How should I manage removal of a solitary cutaneous wart on the left thumb of a 58‑year‑old man (3 mm diameter, 5 mm tall) who is concerned that excision could cause cancer?

Management of a Solitary Thumb Wart with Patient Concerns About Cancer Risk

Reassurance About Cancer Risk

You are correct to reassure the patient that excision or treatment of a common wart does not cause cancer—this is a myth without any scientific basis. 1 The British Association of Dermatologists guidelines explicitly state that warts need to be distinguished from other keratotic lesions including squamous cell carcinoma, but the act of treating or removing a benign wart does not induce malignant transformation. 1 Human papillomavirus (HPV) types causing common hand warts (HPV types 1,2,4,27, or 57) are entirely distinct from the high-risk oncogenic HPV types associated with malignancy. 1

Recommended Treatment Approach

First-Line: Topical Salicylic Acid

Start with topical salicylic acid 15-26% applied daily for 3-4 months, as this has the strongest evidence (Level 1+, Grade A recommendation) for efficacy and safety in treating hand warts. 1, 2

• Instruct the patient to soak the wart in warm water for 5-10 minutes, then gently pare down the thickened white keratin layer using a disposable emery board or pumice stone before each application. 2
• Stop paring if pinpoint bleeding occurs, as this indicates reaching the capillary loops of the dermal papillae. 1, 2
• Apply the salicylic acid preparation daily, ideally with occlusion using a bandage or tape to enhance penetration. 2
• The patient must continue treatment for the full 3-4 months before considering it a failure—premature discontinuation is a common pitfall. 2
• Discard the paring tool after use or dedicate it solely to the wart to prevent spreading infection. 2

Second-Line: Cryotherapy

If salicylic acid fails after 3 months of compliant use, switch to cryotherapy with liquid nitrogen (Grade B recommendation). 1, 2

• Freeze the wart for 15-30 seconds per treatment session. 1, 2
• Repeat treatments every 2-4 weeks for at least 3 months or up to six treatment sessions before declaring failure. 1, 2

Third-Line Options for Recalcitrant Cases

For warts resistant to both salicylic acid and cryotherapy, consider: 2

• Contact immunotherapy with diphencyprone (DPC) or squaric acid dibutyl ester (SADBE), applied from twice weekly to every 3 weeks for 3-6 months (Grade C recommendation). 1, 2
• Intralesional bleomycin (0.1-1 mg/mL) injected into the wart after local anesthesia, requiring one to three treatments, though this is painful during and after treatment (Grade C recommendation). 1, 2
• Pulsed dye laser at 7-10 J/cm² after paring, with two to four treatments typically needed (Grade C recommendation). 1, 2

Alternative: Watchful Waiting

Given that this is a solitary wart in an immunocompetent adult, observation is entirely acceptable if the wart is not causing functional impairment or significant cosmetic distress. 1 Many hand warts resolve spontaneously, with 65% clearing by 2 years and 80% by 4 years in children; rates are lower but still substantial in adults. 2

Critical Pitfalls to Avoid

• Do not stop treatment prematurely—salicylic acid requires a full 3-4 months and cryotherapy needs at least 3 months or six treatments before declaring failure. 2
• Avoid aggressive paring that damages surrounding healthy skin, as this can spread the HPV infection to adjacent areas. 1, 2
• Do not use multiple destructive modalities simultaneously in initial treatment, as this increases scarring risk without proven benefit. 2
• Avoid treatment if the area is inflamed or infected—wait until any secondary infection resolves before resuming therapy. 2

Why Excision Is Not Recommended

While surgical removal by curettage or electrosurgery is sometimes used for filiform (finger-like) warts, it has only Level 3 evidence and Grade D recommendation, and should be reserved for extensive or refractory disease that has failed multiple medical therapies. 3 For a small 3mm solitary wart, destructive surgery carries unnecessary scarring risk when effective topical treatments are available. 1