Modern prevalence of insect sensitization in rural asthma and allergic rhinitis patients

Inhalant allergy to insects other than cockroaches and dust mites was described in the 1950s, but little attention has been paid to these findings. Sensitization rates for many allergens have increased since then. In this rural population, we describe the current prevalence of sensitization to commonly found insects. We evaluated 200 patients (38 adults and 162 children), for immunoglobulin E (IgE)-mediated sensitization to the caddis fly, mayfly, moth, carpenter ant, and housefly using the prick technique and commercially available whole-body extracts. All had symptoms consistent with asthma and/or allergic rhinitis. They also were tested to indoor and outdoor aeroantigens. Of the 200 patients, 60 patients (30%) tested positive to at least one of the five insects. The most prevalent positive skin test was to the mayfly (37/60), followed by the housefly (36/60), caddis fly (27/60), moth (14/60), and ant (10/60). Of the 60 patients positive for insects, 35 patients (58%) also tested positive to at least one species of mite, 36 patients (60%) tested positive to the cockroach. Twelve of the 60 patients (20%) with positive insect testing did not react to either cockroaches or mites. In our patients, the immunoglobulin E-mediated sensitization rate to insects excluding cockroaches is 30%. Many patients also were sensitized to mites and/or cockroaches. These insects are all present in the indoor/outdoor environment of this rural population. Cross-reactivity with mites and cockroaches (insect panallergy) may partially explain our results. The presence of skin test sensitivity in the absence of cockroach or mite allergy suggests possible true insect sensitization.