Risk factors for severe sting reactions and side effects during venom immunotherapy.

Understanding the risk factors leading to severe systemic sting reactions (SSR) is crucial for initiating venom immunotherapy (VIT) and for educating affected individuals and their families. Some of these risk factors are well-established, some are no longer considered risk factors, and some remain controversial. Well-established risk factors for severe SSR include clonal mast cell disease, high baseline serum tryptase, and advanced age. The absence of skin symptoms and the rapid onset of symptoms are indicators of severe SSR. Recent publications indicate that antihypertensive treatment and stings in the head and neck area are not risk factors for severe SSR. VIT is the only available treatment that can potentially prevent further anaphylactic reactions. Although rare and generally manageable, individuals undergoing VIT may experience systemic adverse events (sAE). More sAE are expected in patients undergoing bee VIT compared to vespid VIT. The role of elevated baseline serum tryptase as a risk factor for sAE remains debated, but if it is a factor, the risk is increased by only about 1.5-fold. Rapid up-dosing protocols, depending on the specific regimen, can also be associated with more sAE. Severe initial SSR, antihypertensive medication, high skin test reactivity, and high specific IgE levels are not risk factors for sAE.