What is the recommended treatment for a patient presenting with plantar warts?

Treatment of Plantar Warts

First-Line Treatment: Salicylic Acid

Start with topical salicylic acid 15-40% applied daily for 3-4 months as first-line therapy for plantar warts. 1, 2

• Apply salicylic acid after paring or debriding the wart to remove the thick keratin layer that blocks treatment penetration. 1, 2
• Use occlusion (covering the treated area) if possible to enhance efficacy. 1, 2
• Continue treatment for a full 3-4 months before declaring treatment failure—inadequate treatment duration is a common pitfall. 3, 2
• Expected cure rate is approximately 33% for plantar warts, which is lower than for hand warts due to the thicker cornified layer of plantar skin. 3, 2

Critical caveat: Avoid damaging surrounding normal skin during paring, as this can spread HPV infection to adjacent areas. 1, 3

Second-Line Treatment: Cryotherapy

If salicylic acid fails after 3 months, switch to liquid nitrogen cryotherapy applied every 2 weeks for 3-4 months. 1, 3, 2

• Keep the wart frozen for 15-30 seconds per treatment session. 1
• Expected cure rate is 30-39% for plantar warts. 3, 2
• More aggressive cryotherapy regimens (longer freeze times) may achieve up to 65% efficacy but significantly increase pain, blistering, and scarring risk. 3
• Always pare/debride the wart before each cryotherapy session to maximize penetration. 1, 3

Combination therapy option: Combining salicylic acid with cryotherapy may achieve 86-87% clearance rates and is more effective than either treatment alone. 3, 4

Third-Line Options for Resistant Cases

For warts failing both salicylic acid and cryotherapy, consider these evidence-based alternatives:

• Cantharidin-podophyllotoxin-salicylic acid (CPS) combination: 1% cantharidin + 5% podophyllotoxin + 30% salicylic acid applied every 2 weeks is significantly more effective than cryotherapy alone (complete clearance in 54% vs 42%). 5
• 5-Fluorouracil (5-FU) cream: Apply 5% cream daily under occlusion for 4-12 weeks; achieves 95% clearance in recalcitrant adult plantar warts. 1, 3
• Formaldehyde 3-4% solution: Use as a daily 15-20 minute soak with emollient protection of surrounding skin for up to 8 weeks. 1, 3
• Glutaraldehyde 10% solution: Apply daily after paring for up to 3 months. 1, 3
• Contact immunotherapy with DPC: Achieves 88% complete clearance with median treatment time of 5 months for resistant cases. 3

Important Clinical Considerations

Plantar warts have inherently poor cure rates (14-33%) compared to warts at other body sites due to the thick plantar stratum corneum preventing adequate treatment penetration. 3, 2, 6

• Spontaneous resolution occurs in approximately 30% of cases within 6 months, but waiting may not be acceptable if the wart causes pain or functional impairment. 3
• Patient compliance is often poor with topical treatments due to surrounding skin irritation and prolonged treatment courses required. 3, 2
• More aggressive treatment regimens increase efficacy but also increase pain and scarring risk—this trade-off must be considered. 1, 3

Treatments to Avoid

Do not use surgical excision for plantar warts—it has no high-quality supporting evidence and carries the highest risk of scarring. 3

• Avoid podophyllin during pregnancy due to systemic absorption and toxicity concerns. 1
• Systemic interferon is not recommended due to high cost, frequent adverse effects, and efficacy no better than other available therapies. 1