Development and Validation of a Mobile Clinical Decision Support Tool for the Diagnosis of Drug Allergy in Adults: The Drug Allergy App.

Background: Penicillin allergy overdiagnosis has been associated with inappropriate antibiotic prescribing, increased antimicrobial resistance, worse clinical outcomes, and increased health care costs.

Objective: To develop and validate a questionnaire-based algorithm built in a mobile application to support clinicians in collecting accurate history of previous reactions and diagnosing drug allergy appropriately.

Methods: A survey was completed by 164 medical and nonmedical prescribers to understand barriers to best practice. Based on the survey recommendations, we created a 10-item questionnaire-based algorithm to allow classification of drug allergy history in line with the National Institute for Health and Care Excellence guidelines on drug allergy. The algorithm was incorporated into a mobile application and retrospectively validated using anonymized clinical databases at regional immunology and dermatology centers in Manchester, United Kingdom.

Results: A total of 55.2% of prescribers (95% confidence interval, 47% to 63.4%) thought it impossible to draw a firm conclusion based on history alone and 59.4% (95% CI, 51.4% to 67.5%) believed that regardless of the details of the penicillin allergy history, they would avoid all β-lactams. A drug allergy mobile application was developed and retrospectively validated, which revealed a low risk for misclassification of outcomes compared with reference standard drug allergy investigations in the allergy and dermatology clinics.

Conclusions: Perceived lack of time and preparedness to collect an accurate drug allergy history appear to be important barriers to appropriate antimicrobial prescribing. The Drug Allergy App may represent a useful clinical decision support tool to diagnose drug allergy correctly and support appropriate antibiotic prescribing.