Systemic sting reactions (Table 4)
Taking β-blockers or ACEI had no influence on the severity of the initial sting reaction: 41.7% of patients not taking AHT drugs and 44.1% of patients under antihypertensive treatment had a severe SSR (Grade III or IV; p=0.29). The proportions of severe SSR did not differ significantly between patients taking β-blockers, ACEI, and β-blockers and ACEI with 43.9, 47.9, and 35.2% respectively (p=0.14). The prevalence of cardiovascular diseases or hypertension appeared to be a risk factor (p=0.04). However, this result was biased by patients’ age; when patients’ age was taken into consideration, the effect of cardiovascular disease on the severity of SSR vanished (p=0.91).
We additionally investigated whether bee venom or elevated basal tryptase levels or verified mastocytosis are associated with more severe SSR. Severe sting reactions occurred in 43.4% of patients stung by bees and 41.8% of patients reacting to vespid stings (p=0.50). Elevated basal tryptase levels were associated with more severe sting reactions: 42.0% of patients with normal tryptase levels but 63.8% with elevated tryptase levels had a systemic reaction Grade III or IV (OR: 2.37; 95% CI: 1.61–3.50; p<0.001). The risk for a severe reaction was even 3.7-fold higher for patients with verified mastocytosis compared to patients without mastocytosis (p<0.001).
The parameters age, treatment with β-blockers or ACEI, and tryptase levels were further analyzed in a multivariable model: Antihypertensive treatment still had no influence on the severity of the initial sting reaction (OR: 0.95; 95% CI: 0.72–1.24; p=0.70), and patients with elevated basal tryptase levels still had a 2.4-times higher risk of developing a severe SSR compared with patients with normal tryptase levels (p<0.001).