How Salicylic Acid Works

Salicylic acid has been clinically proven to soften the external layers of warts. This makes it much easier for warts to rub/fall off. When salicylic acid is applied correctly, it is thought to repeatedly irritate the wart, which in turn triggers an immune system response. When the immune system is heightened, it is believed to attack the human papillomavirus (HPV), the virus that causes warts to grow.

Salicylic Acid As a Home Treatment

Salicylic acid is the home treatment most often used in eliminating warts. It is an inexpensive and safe home treatment option and causes minimal or absolutely no pain. Nonprescription salicylic acid is said to be as effective as or more effective than other treatments, with minimal risk and pain. 1 A recent review of research suggests that salicylic acid is a safe treatment that effectively eliminates warts up to 75% of the time. By comparison, placebo or no treatment produced an approximate clearance rate of 50%. 2 There is currently no proof that cryotherapy is any more effective than salicylic acid.

Salicylic Acid Scientific Studies

BACKGROUND:

Plantar warts (verrucae) are extremely common. Although many will spontaneously disappear without treatment, treatment may be sought for a variety of reasons such as discomfort. There are a number of different treatments for cutaneous warts, with salicylic acid and cryotherapy using liquid nitrogen being two of the most common forms of treatment. To date, no full economic evaluation of either salicylic acid or cryotherapy has been conducted based on the use of primary data in a pragmatic setting. This paper describes the cost-effectiveness analysis which was conducted alongside a pragmatic multicentre, randomised trial evaluating the clinical effectiveness of cryotherapy versus 50% salicylic acid of the treatment of plantar warts.

METHODS:

A cost-effectiveness analysis was undertaken alongside a pragmatic multicentre, randomised controlled trial assessing the clinical effectiveness of 50% salicylic acid and cryotherapy using liquid nitrogen at 12 weeks after randomisation of patients. Cost-effectiveness outcomes were expressed as the additional cost required to completely cure the plantar warts of one additional patient. A NHS perspective was taken for the analysis.

RESULTS:

Cryotherapy costs on average £101.17 (bias corrected and accelerated (BCA) 95% CI: 85.09-117.26) more per participant over the 12 week time-frame, while there is no additional benefit, in terms of proportion of patients healed compared with salicylic acid.

CONCLUSIONS:

Cryotherapy is more costly and no more effective than salicylic acid. TRIAL REGISTRATION: Current Controlled Trials ISRCTN18994246 [controlled-trials.com] and National Research Register N0484189151.

Treatment of common warts with high-potency (26%) salicylic acid. Parish LC, Monroe E, Rex IH Jr. Clin Ther. 1988;10(4):462-6. Treatment of common warts with topical keratolytic solutions is generally estimated to result in cure rates of 60% to 80% in 12 weeks. Problems with keratolytic solutions include irritation of surrounding normal skin and poor patient compliance. A product containing 26% salicylic acid in a novel polyacrylic vehicle was evaluated in 27 patients and found to cure or provide much improvement in 22 (81%) after only two weeks of treatment. This rapid response was accompanied by a low incidence of irritation. The results of this study suggest that high-potency salicylic acid promotes prompt resolution of warts, which may enhance patient compliance.

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Citations
1 Gibbs S, Harvey I (2006). Local treatments for cutaneous warts. Cochrane Database of Systematic Reviews (3). Oxford: Update Software.
2 Luk NM, Tan YM (2007). Warts (non-genital), search date November 2006. Online version of BMJ Clinical Evidence. Also available online: http://www.clinicalevidence.com.