Descriptive analysis of a simplified approach to low-risk drug hypersensitivity reactions

Evaluation of drug allergy is intricate because of nonstandardized testing and challenge method variability.

To determine the clinical and epidemiologic characteristics of a large group of patients with suspected drug allergies who underwent 1 or more provocation tests (PT), and to establish whether performing this test in fewer steps is safe and effective.

A cross-sectional descriptive study was conducted in patients with suspected drug allergies who underwent a provocation test at the allergy service of Fundación Valle del Lili, Cali, Colombia, from January 2011 to August 2017.

A total of 508 patients underwent 615 PTs; the median age was 34.5 years (range, 1-87 years) and 332 were women (65.3%). The most frequently implicated drugs were nonsteroidal anti-inflammatory drugs in 362 patients (58.9%), followed by beta-lactam antibiotics in 170 (27.6%), and non-beta-lactam antibiotics in 21 (3.4%). The most typically described manifestations were cutaneous urticaria in 282 patients (45.8%) and angioedema in 220 (35.7%). Most patients underwent the PT without performing other previous tests, which were done in only 92 patients (18.3%). Skin prick tests and intradermal reaction tests were performed in 81 patients (15%); all results were negative. In 519 patients (84.3%), the PT was performed in 2 steps without a placebo. Of the PTs performed in 2 steps, 492 (94.8%) had negative results. In addition, PT was performed in 195 patients (37.6%) in whom 2 equal doses of the drug was administered; 186 patients (95.4%) had negative results.

Performing an open PT (without previous tests) in 2 steps among patients with low-risk drug reactions is safe. However, every case must be analyzed individually in terms of the risk-benefit ratio.