An unusual reaction to topical amethocaine (Ametop) local anaesthetic gel

摘要

Topical amethocaine (Ametop) local anaesthetic gel is used for analgesia in painful procedures in children. While local erythema is a common and well-documented side effect, more significant skin reactions are rare.A 4-year-old boy presented to the emergency department with a short history of swollen knees. No rash was apparent initially, but over several hours, a non-blanching rash developed over his shins and buttocks. There was a history of recent upper respiratory illness with sore throat. Inflammatory markers were raised and a throat swab 'was positive for streptococcus. Antistreptolysin titres were raised. Areas where topical amethocaine local anaesthetic gel was applied became erythematous with a vasculitic rash (figure 1). The degree of erythema was significantly more than usually seen. There was also a distinctive rash around the ankles caused by the elastic from his socks (figure 2). A presumed diagnosis of strep-tococcal-related transient arthritis with vasculitis was made, and the rashes faded over the following week. The arthritis resolved with simple anti-inflammatory medication.