Research indicates that approximately 1 in 3,000 hospitalized patients suffer drug-induced anaphylaxis.  Previous studies investigating anaphylaxis epidemiology used billing codes to broadly determine causes of these life-threatening allergic reactions (eg, drug, food, and venom) but lacked information on specific causative drugs or drug classes. Large-scale studies using EHR allergy lists to describe drug allergy have been infrequent.

At Partners Healthcare System, patient allergy information captured by the EHR allergy module was integrated into the Partners’ enterprise-wide allergy repository (PEAR), resulting in a longitudinal allergy record accessible across the healthcare network. For a study published in The Journal of Allergy and Clinical Immunology: In Practice, my colleagues and I used drug allergy data of patients who visited Brigham and Women’s Hospital and Massachusetts General Hospital between 1995 and 2013 to determine the population prevalence of anaphylaxis, including anaphylaxis prevalence over time and the most commonly implicated drugs/drug classes reported to cause anaphylaxis.

Among approximately 1.8 million patients, 1.1% reported drug-induced anaphylaxis. Penicillins (45.9 per 10,000), sulfonamide antibiotics (15.1 per 10,000), and NSAIDs (13.0 per 10,000) were most commonly implicated. Female gender, Caucasian race, systemic mastocytosis, Sjögren’s syndrome, asthma, and COPD were risk factors for anaphylaxis. We found that serum tryptase was tested in less than 1% of anaphylaxis cases at any time (33% of tests ordered during the correct time window), and only 8% visited an allergist for follow-up during the study period (1.4% within 30 days of anaphylaxis).

The patient-specific risk factors noted above can be used clinically in discussion with patients about drug-induced anaphylaxis. Our findings also emphasize the need to improve the verification of EHR-reported anaphylaxis with tryptase testing and subsequent allergist evaluation.