From the Guidelines
I strongly recommend applying salicylic acid to a wart on the foot for 3–4 months, as stated in the British Association of Dermatologists' guidelines for the management of cutaneous warts 2014 1. To effectively treat the wart, it is essential to use topical preparations of 15–26% salicylic acid, applied daily after removing the thick keratin layer, with occlusion if possible. Some key points to consider when using salicylic acid for wart treatment include:
- Applying the treatment daily, ideally after soaking the foot in warm water for 5-10 minutes and gently filing down the dead skin with an emery board or pumice stone
- Using concentrations of 15-26% salicylic acid, as recommended by the guidelines 1
- Avoiding contact with healthy skin to prevent irritation and other adverse effects
- Considering covering the treated area with a bandage to promote occlusion and enhance the treatment's effectiveness
- Removing any residue from the previous treatment before each new application to ensure optimal results It is crucial to note that salicylic acid works by gradually breaking down the infected tissue and stimulating the immune system to fight the human papillomavirus (HPV) that causes warts. If the wart persists after 3–4 months of treatment, becomes painful, bleeds, or shows signs of infection, it is essential to consult a healthcare provider, as stronger treatments may be needed 1.
From the FDA Drug Label
The preferable method of use is to apply Salicylic Acid 6% thoroughly to the affected area and to cover the treated area at night after washing and before retiring. Preferably, the skin should be hydrated for a least five minutes prior to application The medication is washed off in the morning
The application of salicylic acid to a wart on the foot should be done at night, and the medication should be washed off in the morning.
- Apply for one night, then wash off in the morning.
- There is no specific information on how long to apply it in terms of duration of treatment, only the method of application. 2
From the Research
Treatment of Plantar Warts with Salicylic Acid
- The application of salicylic acid to treat plantar warts is a common practice, with studies suggesting its effectiveness in combination with other treatments 3, 4.
- A study comparing the efficacy of topical salicylic acid application with cryotherapy for cutaneous warts found that cryotherapy was more effective for common warts, but there was no significant difference in effectiveness between the two treatments for plantar warts 5.
- Another study found that a topical formulation consisting of 1% cantharidin, 5% podophyllotoxin, and 30% salicylic acid was more effective than cryotherapy in treating plantar warts 4.
Duration of Treatment
- The duration of treatment with salicylic acid for plantar warts is not explicitly stated in the provided studies, but it is mentioned that treatment can be applied daily or every 2 weeks for up to 5 sessions 5, 4.
- A case report describes a patient with multiple recalcitrant plantar warts who was treated with a cantharidin-podophyllin-salicylic acid formulation for 3 sessions, resulting in complete clearance of the warts 6.
Effectiveness of Salicylic Acid
- A systematic review of topical treatments for cutaneous warts found that salicylic acid significantly increased the chance of clearance of warts at all sites, with a risk ratio of 1.56 (95% CI 1.20 to 2.03) compared to placebo 7.
- The same review found that salicylic acid was more effective for hand warts than for foot warts, with a risk ratio of 2.67 (95% CI 1.43 to 5.01) for hand warts and 1.29 (95% CI 1.07 to 1.55) for foot warts 7.