Academy of Medical Sciences of I.R. Iran Archives of Iranian Medicine 1029-2977 20 1 2017 01 01 Frequency and Risk Factors of Penicillin and Amoxicillin Allergy in Suspected Patients with Drug Allergy 0 0 EN Mohammad Reza Fazlollahi Katayoon Bidad Raheleh Shokouhi Raheleh Dashti Mohammad Nabavi Masoud Movahedi Mohammad Hasan Bemanian Ali Reza Shafiei Najmoddin Kalantari Effat Sadat Farboud Zahra Pourpak Mostafa Moin Journal Article BACKGROUND:Unconfirmed beta-lactam allergy is a significant public health problem because of the limitations it imposes in drug selection. In this study, we aimed to evaluate patients referred for beta-lactam allergy to determine the frequency of confirmed beta-lactam allergy and identify some risk factors. METHODS: In a prospective cohort study, all referred patients to Immunology, Asthma and Allergy Research Institute in Tehran University of Medical Sciences (between 2007 – 2009) who suspected to have beta-lactam allergy were entered into this study based on having the inclusion criteria. Follow-up was performed 6 – 8 years after the final diagnosis. Diagnosis of beta-lactam allergy relies on thorough history and specific IgE measurements (ImmunoCAP), skin prick testing (SPT), intradermal testing (IDT), patch testing, and oral drug challenge test. RESULTS: Fifty-one patients with mean age of 24.5 (±18.5) years were enrolled in this study. Based on workups, beta-lactam allergy was confirmed in 16 (31.4%) patients, suspicious in 22 (43.1%) patients and ruled out in 13 (25.5%) patients. During the follow-up, 3 patients with suspicious drug allergy consumed the culprit drug with no reaction so allergy was finally ruled out in 16 (31.4%) patients. Age, sex, atopy and family history of drug allergies were not significantly different between the patients with confirmed or ruled-out diagnosis of penicillin and amoxicillin allergy. CONCLUSION: At least up to one-third of patients with a history of beta-lactam allergy are proven to be safe using the drug. Also, a clear protocol consists of serum sIgE assay and SPT can be helpful to the physicians in the health care system.