About 3% of the general adult population presents systemic reactions to stings of insects belonging to the order of
Hymenoptera, including honeybees (
Apis spp), bumblebees (
Bombus spp), yellow jackets (
Vespula spp), wasps (
Polistes spp), and hornets (
Vespa spp and Dolichovespula spp). Systemic reactions after
Hymenoptera stings in allergic patients can cause anaphylaxis, with a risk of potentially fatal outcome [
13]. SCIT with
Hymenoptera venom, known as venom immunotherapy (VIT) is highly effective in preventing further systemic reactions, as reported in a systematic review [
14]. VIT is also very safe, since no fatalities after VIT have been reported. Moreover, most of the adverse reactions are usually mild and the necessity of administering adrenalin is rare [
15]. Also the rate of systemic reactions to stings in treated patients is globally low, corresponding to around 3% in adults [
16]. For reasons yet to be completely understood, honeybee VIT has an higher incidence of systemic reactions, that is fivefold more frequent than for wasp venom, especially in build-up phase of VIT [
17]. Korosec et al. [
18] identified as risk factor for severe systemic reactions a short latency from sting and low levels of sIgE for rApi m1. Besides an high profile of safety, VIT is also associated with prevention of fatal reaction in 100% of patients and of any kind of systemic reactions in 90–95% [
19]. In case complete protection is not achieved, increasing the maintenance dose of venom over the standard of 100 μg is recommended and usually permits to reach full protection [
20]. Failure to reach protection is more common in VIT with bee venom than in the one for vespid. Recently Frick et al. [
21] identified sensitization to Api m10 as a risk factor for failure of VIT. Author identified in patients nonresponder to VIT high levels of IgE for Api m10. Correspondingly, low levels of Api m10 were detected in the extracts used for VIT.
Of note, recent data proved that VIT is safe and efficacy also in patients suffering from mastocytosis [
22,
23], making VIT an irreplaceable therapy in this condition.
In conclusion, efficacy and safety of VIT are well established, improving also the disease-specific quality of life of these patients, as reported in a recent review [
15].