We present a case of urticaria caused by antihistamines in a patient with nonsteroidal anti-inflammatory drug (NSAID) sensitivity.
A 35-year-old man experienced, on 2 separate occasions, immediate generalized urticaria during treatment with ibuprofen and naproxen, respectively. A single-blind, placebo-controlled oral challenge (SBPCOC) with piroxicam was carried out, and resulted in urticaria and angioedema 3 hours later. Two hours after initial clinical resolution, the patient developed multiple wheals on the trunk and upper limbs.
He described similar delayed reactions after oral antihistamine administration on previous occasions. SBPCOCs with acetaminophen and etoricoxib were performed, with good tolerance. Skin prick and patch tests with loratadine and cetirizine were negative. After an SBPCOC with loratadine, the patient developed generalized urticaria 90 minutes after intake. Tolerance to fexofenadine 180 mg was confirmed.
We describe the fi rst case of a possible new subset of antihistamine urticaria, and suggest calling this NSAID-sensitive antihistamine induced urticaria/angioedema.

Key words: Antihistamines. Urticaria. NSAID sensitivity.