Epidemiology of allergic occupational diseases induced by Tetranychus urticae in greenhouse and open-field farmers living in a temperate climate area

Background: The role of Tetranychus urticae (TU) as an occupational allerge n has thus far been investigated only in selected farmer samples. Methods: The prevalence of TU-induced sensitization and occupational diseas es in a randomized sample of farmers living in a temperate climate area was investigated. Occupational/nonoccupational symptoms. skin prick test (SPT) results with common allergens and TU, specific Occupational test results. and greenhouse or open-field sources of TU exposure were assessed. The stud y design was cross-sectional. Results: The prevalence of positive SPT to TU was 6%. TU-induced allergic/n onallergic complaints accounted for 65% of farmers with challenge-confirmed occupational disease. In all farmers, sensitization to common allergens wa s a risk factor for both current occupational and nonoccupational complaint s, while TU sensitization was a prominent risk factor for Occupational comp laints. Furthermore, in SPT-positive farmers, only the presence or seasonal occupational complaints was significantly associated with TU sensitization . Common allergen sensitization was a risk factor for development of TU sen sitization. which was more frequent in greenhouse than in open-field worker s. Conclusions: TU was a common nontraumatic, allergic occupational hazard for farmers. Since occupational seasonal symptoms could be directly related to the presence of TU sensitization, allergy to this mite Should be routinely investigated in farmers.