Abstract
BACKGROUND: Penicillin is the only proven effective treatment for pregnant women with syphilis. OBJECTIVE: We evaluated the efficacy and safety of an algorithm to guide reexposure to penicillin in pregnant women with syphilis and a history of allergy to the drug; and identified predictive biomarkers for successful desensitization. METHODS: By using risk stratification, pregnant women with syphilis and a history of immediate hypersensitivity reaction to penicillin were reexposed to the drug through rapid desensitization or drug provocation test. Patients with a high-risk clinical history for anaphylaxis or positive skin test result underwent desensitization. RESULTS: The study included 127 patients. Forty-nine (38.6%) had high-risk clinical history for anaphylaxis and were desensitized, while 78 (61.4%) were at low risk and with negative skin test results underwent challenge. Skin test results were positive in 7.9% of all patients. These patients underwent desensitization, and 40% experienced a reaction. There was an association between positive skin test results and reaction during desensitization (P > .0001). Seventy-eight patients (61.4%) considered to be at low risk were challenged, with only 3 (3.8%) experiencing a reaction. The risk stratification algorithm evaluated in this study demonstrated high efficacy (99.2%) and safety (92.1%) in guiding penicillin reintroduction. CONCLUSION: Our algorithm for managing immediate reactions to penicillin is effective and safe. Skin testing identifies patients at higher risk for reactions. This study enables the identification of pregnant women with a history of high risk for immediate hypersensitivity to penicillin, allowing for safe desensitization treatment, or can offer low-risk pregnant women the option to delabel the allergy through a provocation test.