Third degree formic acid chemical burn in the treatment of a hand wart: a case report and review of the literature

OBJECTIVE: Cutaneous warts are very common and a large variety of topical treatments and drugs can be employed to cure these skin injuries that can arise on any part of the body. But are these products really safe? METHOD: We performed a case description and PubMed literature review using key words “wart,” “chemical burn,” and “formic acid.” All articles in English and French were selected. RESULTS: This is the first report of a chemical burn by formic acid in the treatment of warts. Numerous topical treatments for cutaneous warts are available with many new drugs appearing every year. However, only a few treatments have proven their effectiveness, such as salicylic acid or cryotherapy with liquid nitrogen that are commonly used. Moreover, most cutaneous warts will resolve spontaneously without any treatment and several products, including topical acids and cryotherapy devices, presented adverse effects such as chemical burns or frostbites so demonstrating that even frequently used treatments can be harmful. CONCLUSION: Topical treatments used for wart removal are not without risk even if some products are sold without prescription. For self-treatment products, we recommend enhanced warning by the pharmacist about the risks involved.