Severe Allergic Reaction Following Administration of Antivenom Serum for Snakebite: A Case Report from Togo

Background: Ophidian envenomation is common in Sub-Saharan Africa, and its management is hampered by the lack of access to healthcare services in rural areas, in particular the availability and appropriate use of antivenom. Rare cases of serious side effects following the administration of antivenom have been reported. This is the case for a young farmer from the central region of Togo, who experienced a second snake bite within four years, and in whom antivenom serotherapy led to severe allergic manifestations. Case presentation: This 24-year-old patient, with a history of antivenom and tetanus serotherapy, was admitted to the Centre Hospitalier Régional (CHR) of Sokodé for a snakebite that occurred 45 minutes earlier while working in the field. Clinical assessment on admission revealed grade 1 envenomation, characterized by local pain in the right upper limb, with no sign of complication. He received an intravenous infusion of antivenom serotherapy, which rapidly relieved the pain, allowing him to be discharged after 24 hours of hospital monitoring. However, he was readmitted five days later for a skin rash associated with generalized pruritus and edema of the face and the neck, which prompted his evacuation to the Sylvanus Olympio University Hospital. He was diagnosed with a hypersensitivity-type allergic reaction to antivenom serum. Symptomatic treatment with antihistamines resulted in a favourable outcome after five days in the hospital. Conclusion: This young farmer developed a severe allergic reaction following a second course of antivenom serotherapy for low-grade ophidian envenomation. Although the efficacy of antivenom serum is undeniable in the management of snakebites, its use should be guided by a sound clinical assessment and framed by rigorous monitoring, especially in people sensitized to antivenom or antitoxin serotherapy. This highlights the importance of training healthcare staff alongside the availability of anti-venomous sera at peripheral healthcare centres.