Occupational airborne contact dermatitis caused by thyme dust

The aim of the study was to assess occupational hazards to the farmer's skin associated with processing thyme (Thymus vulgaris L.). 46 farmers were studied during the threshing of dried thyme. They were questioned about work-related skin problems and examined before and after work. In all persons, serum thyme-specific IgE was measured. Skin prick tests, the Ouchterlony test and the migration inhibition test were carried out with allergens of airborne bacteria and fungi present in the working environment. Of the 46 farmers studied, 4 showed skin symptoms after 5-30 min of exposure to thyme dust. Thyme-specific IgE was found in 1 person with work-related symptoms, but also in 2 asymptomatic farmers. Therefore, the importance of IgE seems to be questionable in eczema related to thyme dust. Skin and blood tests with microbial allergens also showed no significant differences between the symptomatic and asymptomatic farmers. To our knowledge, this is the 1st description of occupational airborne contact dermatitis caused by thyme dust. The etiology of thyme-related skin symptoms remains obscure, although an irritant mechanism seems probable