Acetaminophen anaphylaxis diagnosed by skin prick test.
Acetaminophen (Paracetamol) is the most common medication for pain and fever. There are many case reports of severe cutaneous adverse reactions induced by acetaminophen such as anaphylaxis; however, only a few cases of IgE mediated hypersensitivity proved by a skin prick test (SPT) have been reported.1e3 We described here the first case of acetaminophen anaphylaxis diagnosed by SPT in Japan, and reviewed 5 case reports of acetaminophen immediatetype reaction in Japanese patients. A 20 year old woman visited our department following a recent episode of anaphylaxis. Carbocysteine, acetaminophen, garenoxacin mesylate and tranexamic acid for tonsillitis were prescribed. A few minutes after administration of these drugs the patient developed urticaria and dyspnea. To identify the cause of the anaphylaxis, a SPT was performed. The results were positive for 100 mg/ml acetaminophen in saline (2th) within 15 min after application (Fig. 1a) whereas the results for the other drugs were negative. Additional SPTs later yielded positive results for 100 mg/ml acetaminophen (2th) and 10 mg/ ml acetaminophen (2th) but the reaction to 1 mg/ml acetaminophen (1th) manifested as less than 50% of the wheals produced by histamine, and was therefore not considered clinically significant (Fig. 1b, c) Negative reactions to 100 mg/ml acetaminophen by SPT were confirmed in 5 healthy volunteers. Based on these SPT results, IgE mediated anaphylaxis due to acetaminophen was diagnosed. Because of the severity of her clinical episode, intradermal and oral provocation tests (OPT) were not performed. The patient had no history of allergy to any food or medication. She had been working as a care taker for the aged for 3 years and often administered acetaminophen to the elderly. Consistently with the SPT results, she complained itchiness on the thumb and fingers after touching acetaminophen. Following its introduction in 1893, acetaminophen has been prescribed as an antipyretic and analgesic worldwide.4 Although the safety and efficacy of acetaminophen are well established, several case reports exist of severe cutaneous adverse effects such as Stevens Johnsons syndrome, toxic epidermal necrolysis, acute generalized exanthematous pustulosis, and anaphylaxis resulting from its use.3 In a recent report, 13 of 333 (3% or 2 of 313 (0.6%
Allergology international official journal of the Japanese Society of Allergology