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Venom allergy is a potentially life-threatening hypersensitivity reaction to stinging insect venoms, most commonly from bees, wasps, hornets, yellow jackets, and fire ants. Reactions can range from mild local swelling to severe systemic anaphylaxis, which can be fatal without prompt treatment. This IgE-mediated allergic response affects approximately 0.4-0.8% of children and up to 3% of adults.
Venom allergy involves a Type I hypersensitivity reaction mediated by IgE antibodies specific to venom proteins such as phospholipase A2, melittin, and hyaluronidase. Upon initial exposure, these proteins act as allergens, leading to IgE production and mast cell/basophil sensitization. Subsequent venom exposure triggers rapid degranulation of these cells, releasing inflammatory mediators including histamine, leukotrienes, and cytokines that cause vasodilation, increased vascular permeability, smooth muscle contraction, and potential cardiovascular collapse.
Diagnosis requires a detailed history of sting exposure and reaction severity, supported by venom-specific IgE testing or skin prick tests to identify the culprit insect. Patients with documented systemic reactions should be prescribed epinephrine auto-injectors and receive education on avoidance strategies and emergency management. Venom immunotherapy is highly effective (95% success rate) for preventing future severe reactions and should be considered for patients with systemic reactions to prevent potentially fatal anaphylaxis.