Hypersensitivity to cyclooxygenase inhibitory drugs in children: a study of 164 cases.

Hypersensitivity to cyclooxygenase (COX) inhibitors is rare in children. We studied 164 children reporting 213 reactions to paracetamol, ibuprofen and/or acetylsalicylic acid (ASA). Most reactions were cutaneous, either isolated or associated with respiratory symptoms and/or anaphylaxis. Based on a convincing clinical history or positive responses in challenges with the drug(s), hypersensitivity to one or several drug(s) was diagnosed in 49.4% of the children (60, 76.5 and 23.2% of the children reporting reactions to ASA, ibuprofen and paracetamol respectively). Cross-reactivity between nonsteroidal anti-inflammatory drugs (NSAIDs) was frequent (69.1%), but only 10.6% of the NSAID-sensitive children reacted to paracetamol. In contrast, all paracetamol-sensitive children reacted to NSAIDs. Anaphylaxis, immediate and accelerated reactions, atopy, older age and chronic/recurrent urticaria were risk factors for hypersensitivity and/or cross-reactivity between ASA, ibuprofen and paracetamol. In conclusion, hypersensitivity to COX inhibitors was frequent, especially in children reporting severe and/or immediate and accelerated reactions, and in older and atopic children. Cross-reactivity was frequent, suggesting that most reactions resulted from a non allergic hypersensitivity linked to the pharmacological properties of the drugs. However, in a few children, the reactions may result from allergic hypersensitivity to selective (families of) drugs, with tolerance to other drugs.