Evaluation of Allergic Reactions Following Intravenous Infusion of Polyvalent Antivenom in Snakebite Patients

Background: Antivenom is a gold-standard treatment for snakebite envenoming. However, adverse reactions to snake antivenom are common in many parts. Objective: The aim of this study was to evaluate the allergic reactions following intravenous administration of antivenom sera. Methods: This was retrospective study conducted on snakebites patients referred to the Rahimi Hospital in Khorramabad. The files of these patients were accessed for demographic data, snakebite-related data, treatment provided, clinical presentation and allergic reaction status as a result of antivenom treatment. Results: 141 cases were investigated, including 73.8% male and 26.2% female patients. The mean age of the patients was 38.1±17.1 years. Age group 30-39 years accounted for the highest number of snakebite cases (24.1%). A majority of victims (89.4%) were from rural areas. Most of the patients (51.8%) were bitten in the spring and highest number of snakebite were reported in May (39.1%). The most common site of snakebite was lower extremities (50.4%) and upper extremities (44.7%). Among clinical feature of snakebite, pain was the most prevalent in 135 cases (95.7%) followed by swelling (83.7%). The mean antivenom vials used were 6.5±3.7 vials. Allergic reactions occurred in 6 patients (4.26%); reactions were mild in 5 patients and severe in 1 patient. The commonest presentation was maculopapular rash (1.4%) and the least common were headache (0.71%), nausea (0.71%), fever (0.71) and hypotension (0.71%). Conclusion: Snakebite is one of the significant life-threatening environmental events. Immediate antivenom treatment can reduce mortality however, patients should be carefully monitored for adverse allergic reactions