Hymenoptera-induced hypersensitivity reactions and anaphylaxis

Abstract

Most Hymenoptera (honeybees, bumblebees, yellow jackets, hornets, wasps and fire ants) stings lead to a local reaction. Up to 7% of population develops systemic allergic reaction to the constituents of venom. Up to 0.5 per one million people die per year due to Hymenoptera venom allergy. Risk factors for the most severe reactions are advanced age, concomitant cardiovascular diseases, concomitant treatment with beta-blockers or angiotensin-converting enzyme inhibitors, mastocytosis, and European hornet (V. crabro) allergy. In a patient presenting with a history of Hymenoptera-induced reactions, the severity of the reaction should be assessed, and responsible insect should be identified. Both answers are critical when specific venom immunotherapy (VIT) is considered for treatment. VIT is the only effective treatment for the prevention of serious allergic reactions to Hymenoptera stings in sensitized individuals. Contraindications for VIT are not as strict as they are for respiratory allergic diseases. In patients at high risk for anaphylaxis, VIT should be done under careful supervision even if it is not possible to take the patient off beta-blockers. VIT is safe and effective in patients with a malignant disease in remission and in autoimmune diseases. The optimal duration of VIT is 5 years. Longer or even lifelong treatment should be considered in patients with systemic mastocytosis, near death anaphylaxis, patients with systemic allergic reactions to immunotherapy injections or stings during VIT and highly exposed patients, such as beekeepers. Nearly complete tolerance is established after only a few days of rush immunotherapy. Long-term effectiveness after stopping immunotherapy is less reliable. In patients with venom induced anaphylaxis, mastocytosis should be actively investigated by testing the baseline serum tryptase level and by a clinical examination searching for characteristic skin lesions. VIT in those patients is associated with a higher rate of severe side effects. VIT is recommended for life because there are some case reports of fatal reactions after stopping venom immunotherapy. © 2011 Springer Science+Business Media, LLC.