Exposure and sensitization to insects in allergic patients in the tropics

Introduction: Mites are an important source of allergens in the tropics. Other potential sources of allergens prevalent in the region such as insects have been poorly studied. Objective: To determine the relationship between exposure and allergic sensitization to cockroaches, mosquitos, ants and the interaction with mite sensitization. Materials and methods: We included patients with allergy tests for Blatella germanica, Aedes aegypti, Solenopsis invicta, Blomia tropicalis, Dermatophagoides farinae and D. pteronyssinus. IgE sensitization was evaluated by intraepidermal tests. Exposure to insects in houses was evaluated using traps for crawling and flying insects. Results: A total amount of 186 patients were included; 73 (39.2%) of them were sensitized to an insect (cockroaches: 21%, mosquitoes: 29%, ants: 26,3%), 71 (97.2%) also had sensitization to mites. Of the 148 patients sensitized to mites, only 47.9% were sensitized to an insect. In total, 104 houses were evaluated: 74% had cockroaches, 22% ants, and 52% mosquitoes. Among insect-sensitized patients, the number of insects at home was directly related to the size of the weal generated during the skin test: Cockroaches, r=0.781, p<0.001; mosquitoes, r=0.811, p<0.001, and ants, r=0.840, p<0.001. Conclusion: Sensitization to insects is frequent in allergic populations of the tropics and is strongly associated with sensitization to mites.