Background: To date there has been an absence of nation-wide epidemiologic studies on insect allergy in Spain.

Objectives: To measure the frequency and to determine the characteristics of Hymenoptera hypersensitivity in a Spanish population at a particular point in time and compare with the data obtained in a similar study carried out in 1992.

Material and Methods: An observational, prospective and cross-sectional study (Alergológica-2005) was carried out all over Spain.

Results: The number of patients included in the study was 4991, of whom 77 (1.54%) were diagnosed with insect sting allergy. This represented an increase of 0.7% compared to Alergológica-1992. The honey bee was responsible for 45.5% of reactions, Vespula spp for 27.3% and Polistes spp for 23.4%. 64.9% of reactions were systemic. The group with Hymenoptera allergy had a predominance of males (69.1% vs.
42.7% in the general sample, P < .0001), older patients (median age 37,4 vs. 32,1, P < .013), and homes in rural zones (33% vs. 18.3%, P < .004). The median of days necessary to reach a diagnosis was lower (P < .0001). This population needed assistance in emergency units and hospitalisation more frequently. They had a low score on the mental component of the quality of life questionnaire.

Conclusions: There was an increase in cases diagnosed with insect allergy with regard to Alergológica-1992. The typical patient profile is of a man, living in a small village, working outdoors with signifi cant exposure to insect stings and in contact with farm animals, without atopic diseases. Bees and wasps are equally responsible of the stings. The need of emergency assistance in those patients is higher and the waiting time to be attended by an allergist is shorter.

Key words: Hymenoptera. Allergy. Epidemiology. Cross-sectional study.