Food-dependent NSAID-induced hypersensitivity reactions (FDNIH): unraveling the clinical features and risk factors.

BACKGROUND In up to 70-80% of patients with a suspected non-steroidal anti-inflammatory drug hypersensitivity (NSAIDH) challenge tests with the culprit drug yield negative results. On the other hand, there could be a NSAIDH overdiagnosis when anaphylaxis is the clinical manifestation. We hypothesize that some negative NSAID challenge tests and an overdiagnosis of NSAIDH occurs in patients with food-dependent NSAID-induced hypersensitivity (FDNIH). METHODS We studied 328 patients with a suspected acute NSAIDH. FDNIH was diagnosed in patients meeting all the following: 1) tolerance to the food ingested more temporally closed before the reaction, later the episode, 2) respiratory or cutaneous symptoms or anaphylaxis related to NSAID, 3) Positive skin prick test to foods and/or specific IgE to food allergens (Pru p 3, Tri a 19, Pen a 1) involved in the reaction and 4) Negative oral provocation test to the culprit NSAID. RESULTS 199 patients (60%) were diagnosed with NSAIDH and 52 (16%) with FDNIH. Pru p 3 was involved in 44 cases (84.6%), and Tri a 19 in 6 cases (11%). FDNIH subjects were younger (P<0.001), with a higher prevalence of rhinitis (P<0.001) and previous food allergy (P<0.001), together with a higher proportion of subjects sensitized to pollens (P<0.001), and foods (P<0.001). Using just four variables (Pru p 3 and Tri a 19 sensitization, anaphylaxis and any NSAID different from pyrazolones), 95.3% of cases were correctly classified, with a sensitivity of 92% and specificity of 96%. CONCLUSION Evaluation of FDNIH should be included in the diagnostic work up of NSAIDH.