Characteristics of Adverse Drug Reactions Associated with Iron Drugs and Results of Drug Provocation Tests: A Single-Center Experience in Tertiary Care

INTRODUCTION: Iron drugs are frequently prescribed in primary care for the treatment of iron deficiency anemia, while parenteral drugs are used in patients with malabsorption or intolerance to oral drugs. Gastrointestinal side effects are common after oral iron, whereas hypersensitivity reactions (HSRs) may occur less frequently but with both oral and parenteral drugs.
METHODS: We retrospectively evaluated 39 adult patients (2021–2024) referred to the Immunology and Allergic Diseases Clinic with suspected iron drug allergy. Clinical features, reaction severity, and results of alternative or diagnostic drug provocation tests (DPTs) were analyzed.
RESULTS: The study included 36 females and 3 males, with a median age of 40 years (range 20–77). Initial reactions were IgE-mediated HSRs in 82% and non-allergic side effects in 18%. Most IgE-mediated HSRs (79%) were mild (Grade 1), with 12% classified as severe (Grade 3). The most frequently suspected drug was iron carboxymaltose (43.6%). DPTs were performed with alternative iron drugs in 82% and for diagnostic purposes in 18% of cases. Negative results were obtained in 87% of DPTs, while 13% were positive; all positive reactions were mild (Grade 1) and most commonly associated with iron carboxymaltose. Desensitization with iron carboxymaltose was successfully performed in three patients without alternative treatment options.
DISCUSSION AND CONCLUSION: Although non-allergic side effects are more common, IgE-mediated HSRs to iron drugs remain a clinically significant concern due to their potential severity, including rare anaphylaxis. Cutaneous symptoms were the most frequent presentation. Any skin manifestations during iron therapy should prompt discontinuation of the drug and referral to an allergy specialist for further evaluation.