Challenge-based clinical patterns of 223 Spanish patients with nonsteroidal anti-inflammatory-drug-induced-reactions.

BACKGROUND The single-blind, placebo controlled oral challenge (SBPCOC) is the definitive way to diagnosis nonsteroidal anti-inflammatory drug (NSAID)-induced reactions. OBJECTIVE To evaluate 223 NSAID-sensitive patients by means of SBPCOC, and to describe the main clinical patterns found. METHODS A prospective study was carried out, including 2 patient groups with case histories consistent with NSAID-induced reactions. Of the 223 patients, 174 were diagnosed on the basis of a positive SBPCOC. The second group consisted of 49 patients who were referred because of a documented history of anaphylaxis after taking NSAIDs, and these underwent SBPCOC with potent cyclooxygenase (COX)-1/COX-2 inhibitors, except those reported as being responsible for the reaction. The type of SBPCOC reaction, the NSAID reactivity pattern, and the associated diseases were the main classification criteria. RESULTS Two broad categories of NSAID-induced reactions were identified: the cross-reactive and selective syndromes. The 150 patients who showed cross-reactive syndromes included 3 types of diseases: type 1, patients with rhinitis and/or asthma who developed nasoocular and/or asthmatic reactions (n=40); type 2, patients with or without chronic urticaria who presented urticaria/angioedema (n=59); and type 3, atopic patients with isolated periorbital angioedema (n=51). In contrast, the selective syndromes, or type 4, included 50 patients who developed anaphylaxis, as well as 11 patients with urticaria during SBPCOC. Finally, a miscellaneous group of reactions not matching any of the above types was identified (n=1 2). CONCLUSIONS NSAID-sensitive patients can be classified into 4 different groups of reactors, each with well-defined clinical characteristics. Thus, a clinical classification of this NSAID-induced reaction complex is proposed.