Venom skin tests in insect-allergic and insect-nonallergic populations

Intradermal skin tests with varying concentrations of honeybee, yellow jacket, white-faced hornet, yellow hornet, and Polistes venoms were done on 85 patients with histories of insect-sting anaphylaxis and on 56 insect-nonallergic subjects. Positive skin tests (wheal greater than or equal to 5 to 10 mm and flare greater than or equal to 11 to 20 mm) were present in 67 insect-allergic patients at venom concentrations ranging from 0.001 microgram/ml to 0.1 microgram/ml. Seven additional allergic patients had positive skin tests with the 1.0 microgram/ml venom concentration. Twenty-six nonallergic subjects had positive skin tests at the venom concentration of 1.0 microgram/ml, and two patients had positive skin tests at the lower venom concentrations (0.001 to 0.1 microgram/ml). These results confirm venom skin tests as a highly sensitive method of detecting venom-specific IgE in the evaluation of patients with stinging-insect hypersensitivity. Since a large percentage of insect-nonallergic subjects reacted to the 1.0 microgram/ml concentration, clinical judgment and further in vitro testing should be considered in the evaluation of patients who react only at this venom concentration.