Introduction: Chemical burns are comparably rare but often result in full-thickness skin defects with frequent involvement of underlying structures. Hands are the most commonly affected injury site and impaired functional outcome is common. We present a case of an unusual chemical burn to the dorsum of the hand of a child secondary to application of a topical anti-wart treatment containing formic acid. Case report: An 11-year-old girl was referred to our outpatient department with a full-thickness injury resulting from a chemical burn having used a topical formic acid solution in the treatment of common warts. On examination, a 20-mm circular full-thickness defect was noted to the dorsum of the hand. The extensor tendons were not involved and there were no signs of infection. She required surgical debridement and local flap coverage. The postoperative recovery was unremarkable. Conclusion: Through a comprehensive literature review, four common topical solutions used in anti-wart treatment were identified to be associated with burns. Together with our case, this highlights the importance of careful patient education in the usage of common topical over-the-counter treatments.
Lay Abstract Viral warts to the skins are common and are expected to heal by themselves with time. However, they can be associated with stigma and discomfort, leading many people to seek treatment for their removal. There are many different types of treatment options, the most common being to freeze them (cryotherapy) or using a solution that is painted on to the wart. Recently, there has been a rise in the number of different types of solutions that are used in the treatment of warts, including formic acid. Here we describe a case of an 11-year-old girl who used a formic acid-based solution to treat a wart on her hand. This resulted in a deep chemical burn that required surgery under local anaesthetic. She did not have any immediate complications from her surgery. On reviewing the literature, we identified two other acid-based solutions, salicylic acid and monochloroacetic acid, and a third chemical called other glutaraldehyde, that are commonly found in anti-wart treatments and have been described to cause chemical burns. These anti-wart treatments are widely available over the counter and we would like to highlight the importance of proper patient education when used to minimise the risk of chemical burns.