From shore to sequelae: delayed hypersensitivity reaction mimicking softtissue infection following stingray envenomation: a case report.

INTRODUCTION: Stingray envenomation is a relatively common occurrence among water sports enthusiasts, including swimmers, scuba divers, and surfers, as well as among fishermen. However, there is a lack of medical literature on the pathophysiology of immediate and delayed hypersensitivity reactions and, more importantly, on the range of bacterial and mycobacterial infections that can result from these envenomation injuries. This paper aims to provide a general overview of the mechanisms, diagnostic challenges, and management of late hypersensitivity reactions and infections that can occur following stingray stings.

CASE REPORT: A 63-year-old man with well-controlled hyperlipidemia presented to the Mayo Clinic with a 1-week-old injury from accidentally stepping on a stingray barb while walking on a beach in Ventura, California. Immediate pain was relieved with immersion in warm water. He did not take any over-the-counter or prescription medications, and over the following days, he returned to his usual activities of cycling, running, and swimming with minimal discomfort. There was no initial redness or swelling at the puncture site, but he reported intermittent sharp, localized pain with movement leading up to his hospital visit. A biopsy was performed due to concern for a developing necrotic infection, and he was diagnosed with a hypersensitivity reaction. He was initially treated with intravenous antibiotics, and steroids were added based on biopsy results. After completing his treatment course, his hypersensitivity reaction fully resolved over several weeks.

CONCLUSION: This case underscores the importance of considering both immediate and delayed hypersensitivity reactions that can result from stingray envenomation. These reactions can be managed with conservative measures, such as warming the affected area in a water bath to denature heat-labile venom, as well as with conventional therapies, including topical or systemic antihistamines and steroids. It also highlights the need for early empiric antibiotic coverage and outlines the infectious agents implicated in early- and late-onset infections following stingray envenomation, including Pseudomonas aeruginosa, Vibrio vulnificus, and Mycobacterium fortuitum. Additionally, it emphasizes the need for tetanus vaccine updates, radiography, and a multidisciplinary approach to treating stingray injuries.