What is the recommended stepwise management of viral warts in immunocompetent patients (children, adolescents, and adults), including first‑line and second‑line treatment options?

Management of Viral Warts in Immunocompetent Patients

Start with topical salicylic acid 15–40% applied daily after proper debridement for a full 3–4 months as first-line therapy; if this fails, switch to liquid nitrogen cryotherapy every 2 weeks for 3–4 months as second-line treatment. 1, 2

Initial Decision: Treat or Observe?

Watchful waiting without treatment is entirely acceptable for immunocompetent patients with asymptomatic warts, particularly in children, since spontaneous resolution occurs in approximately 65% by 2 years and 80% by 4 years. 1, 3 However, treatment should be initiated when warts cause pain, functional impairment, significant cosmetic concern, or risk of spread. 1, 2

First-Line Treatment: Salicylic Acid

Apply salicylic acid 15–40% daily for a continuous 3–4 month period before declaring treatment failure. 1, 2 This recommendation carries the highest level of evidence (Level 1+, Grade A) from the British Association of Dermatologists. 1

Proper Application Technique

• Soak the wart in warm water for 5–10 minutes before each application to soften the thickened keratin layer. 4
• Gently pare or debride the wart surface using a disposable emery board, pumice stone, or callus file, removing only the white hyperkeratotic layer. 2, 4 Stop immediately if pinpoint bleeding occurs, as this indicates reaching the dermal papillae. 4
• Apply the salicylic acid preparation once daily after paring. 2, 4
• Consider occlusion with a bandage or tape after application to enhance drug penetration and effectiveness. 2, 4
• Discard the paring tool after use or dedicate it solely to the wart to prevent viral spread. 4

Critical Pitfalls to Avoid

• Do not discontinue treatment before completing the full 3–4 month course, as premature cessation is the most common cause of treatment failure. 2, 3
• Avoid aggressive paring that damages surrounding healthy skin, as injury can disseminate the virus to adjacent tissue. 2, 4
• Do not treat large surface areas simultaneously in children under 12 years, to prevent systemic salicylate absorption and toxicity. 2, 3

Special Considerations for Children

In children under 12 years, limit the treatment area and monitor for signs of salicylate toxicity (tinnitus, nausea, vomiting, hyperventilation, confusion). 2, 3 Avoid use during varicella infection or influenza-like illnesses due to Reye syndrome risk. 2, 3

For children under 5 years, use concentrations of 15–26% rather than 40% to reduce toxicity risk. 3 For plane warts, use lower concentrations (2–10%) or cautious application of 12–17% without occlusion to avoid scarring. 4

Site-Specific Considerations

Plantar warts have lower cure rates than warts at other sites due to the thicker cornified layer that impedes drug penetration; thorough debridement before each application is therefore critical. 2, 4 Slightly stronger preparations (20–30%) may be beneficial for plantar warts after adequate paring. 2

Second-Line Treatment: Cryotherapy

If salicylic acid fails after 3 months, switch to liquid nitrogen cryotherapy applied every 2 weeks (fortnightly) for 3–4 months or up to six treatments. 2, 4, 3 More frequent treatment intervals (weekly) achieve faster clearance but require the same total number of treatments. 5

Cryotherapy Technique

• Freeze the wart for 15–30 seconds per treatment session. 4
• In pediatric patients, use milder freeze settings to minimize pain and blister formation. 2, 4
• Continue treatment for at least 3 months or six sessions before declaring failure. 4, 3

Comparative Effectiveness

Cryotherapy is more effective than salicylic acid but carries a higher risk of side effects (pain, blistering). 6 Cure rates after 3 months of weekly cryotherapy reach 43% (66% of compliant patients), compared to 37% with 2-weekly treatment and 26% with 3-weekly treatment. 5

Combination Therapy

When monotherapy fails, combine daily salicylic acid application with fortnightly cryotherapy sessions, acknowledging a higher risk of local adverse effects (irritation, blistering). 2, 3 More aggressive combination protocols may improve clearance rates but increase side effects. 2, 3

Third-Line Options for Recalcitrant Warts

When both first- and second-line therapies fail after adequate trials:

Topical Chemotherapy

Topical 0.5% 5-fluorouracil combined with 10% salicylic acid yields markedly higher clearance (63%) than salicylic acid alone (11%) in meta-analysis of randomized studies. 2 Intralesional 4% 5-FU (mixed with lidocaine and adrenaline) administered weekly for up to four injections achieves approximately 65% complete clearance. 2

Alternative Destructive Agents

• Glutaraldehyde 10% solution applied topically results in roughly 72% cure of resistant plantar warts, though repeated use carries risk of deep tissue necrosis. 2
• Daily 15–20 minute soaks in 3–4% formaldehyde solution produce approximately 80% cure rate in pediatric patients with plantar warts. 2
• Topical 2% dithranol cream achieves 56% cure rate, significantly higher than 26% with salicylic acid/lactic acid combination in randomized controlled trial. 2

Immunotherapy

Contact immunotherapy with diphencyprone (DPC) or squaric acid dibutyl ester (SADBE) can be applied at appropriate strength from twice weekly to every 3 weeks for 3–6 months (Evidence Level B). 4

Procedural Options

• Intralesional bleomycin (0.1–1 mg/mL) injected after local anesthesia, with one to three treatments typically needed, though this is painful (Evidence Level C). 4
• Pulsed dye laser (7–10 J/cm²) applied after paring and/or salicylic acid pretreatment, with two to four treatments usually needed (Evidence Level C). 4

Common Clinical Pitfalls

• Do not use multiple destructive modalities simultaneously in initial treatment, as this increases scarring risk without proven benefit. 4
• Do not stop treatment prematurely; salicylic acid requires 3–4 months and cryotherapy needs at least 3 months or six treatments before declaring failure. 2, 4
• For filiform (finger-like) warts on hands, curettage or hyfrecation may be more appropriate than topical treatments. 4
• Patient compliance with salicylic acid is often poor due to irritation of surrounding skin; address this proactively with proper application technique and realistic expectations. 2

Age-Specific Algorithm

Children Under 5 Years

1. Watchful waiting is the most appropriate initial approach, as painful treatments should be avoided in this age group. 3
2. If treatment necessary: Salicylic acid 15–26% for 3 months. 3
3. If failure: Gentle cryotherapy fortnightly for 3–4 months. 3

Children 5–12 Years and Adolescents

1. Salicylic acid 15–40% for 3–4 months. 2, 3
2. If failure: Cryotherapy every 2 weeks for 3–4 months. 2, 3
3. If failure: Combination therapy or third-line options. 2, 3

Adults

1. Salicylic acid 15–40% for 3–4 months. 1, 2
2. If failure: Cryotherapy every 2 weeks for 3–4 months. 1, 2, 4
3. If failure: Combination therapy or third-line options (5-FU, immunotherapy, laser). 2, 4