Skin reactions to allergens from processionary caterpillars (genus Thaumetopoea)

Abstract

Background: Moths of the genus Thaumetopoea are widespread pests in the coniferous and deciduous forests in Bulgaria. Contact with the caterpillars, larval form of different Thaumetopoea species, causes a series of complaints in humans: mainly contact dermatitis (erucism), but also IgE-mediated allergic reactions. The aim of the present pilot study is to investigate the skin reaction after prick tests with allergens from different Thaumetopoea species in a group of people who have frequent contacts with the processionary caterpillars. Material and methods: A group of 42 subjects were surveyed - 37 men and 5 women between the ages of 18 and 87. Specific sensitization to caterpillars of three Thaumetopoea species: Thaumetopoea pityocampa (pine processionary); Thaumetopoea processionea (oak processionary) and Thaumetopoea solitaria (pistachio processionary) was assessed by allergy skin prick tests (SPT) with specially designed caterpillar allergens. Results: Positive allergy skin tests to one or more caterpillar’s allergens were measured in 18 (43%) participants. A simultaneous test with the three allergens from the different Thaumetopoea species showed that in 5 (31%) of the cases, skin hypersensitivity only to allergen from T. pityocampa was present. Monosensitization to T. processionea observed in 2 (12%). The rest 9 (57%) participants with positive skin test show different profiles of polysensitization to Thaumetopoea allergens under study. Conclusions: The evaluation of skin reactivity after SPT with different caterpillar’s allergens outlined the important role of processionary allergens, especially this from T. pityocampa, in the development of IgE-mediated allergic complaints in different groups of forestry professionals. In view of these results, it seems that IgE-mediated hypersensitivity allergic reactions to Thaumetopoea caterpillars are at least as important as those with no allergic mechanism.