Drug-induced fixed urticaria because of hypersensitivity to non steroidal anti-inflammatory drugs

Abstract

Drug-induced fixed urticaria (DIFU) is a rare skin reaction, characteri zed by pruritic hives that reappear in the same location after exposure to the triggering drug. In the few cases reported in the literature, it is considered as an atypical variant of fixed drug eruption (FDE). We present the case of a 10-year-old girl with allergic rhinoconjunctivitis, who had experienced three episodes of localized urticaria on the dorsal surface of both arms, 1 hour after taking ibuprofen. These manifestations did not appear when taking paracetamol, which she tolerated. Her father suffers from generalized urticaria to NSAIDs. An oral provocation test (OPT) was performed with ibuprofen, acetylsalicylic acid, and metamizole, which also caused the same fixed-location wheals and subsequent spontaneous resolution. She, however, tolerated an OPT with meloxicam. This case is notable because of the rarity of the DIFU and the familial aggregation of hypersensitivity to NSAIDs. In this case, as in those of DIFU described in the literature, the hives appeared shortly after the drug was administered and resolved rapidly. This feature distinguishes it from FDE, and it resembles acute drug urticaria, as in the patient’s father, which raises questions concerning the pathophysiology of DIFU.