With about 14,000 species, the Basidiomycetes comprise the morphologically largest fungi. The frequency of a stand fungus-sensitization corresponds approximately to that of the molds (Alternaria, Cladosporium, Aspergillus, Fusarium see below molds). Sensitization rates of 10-32% to one or more stand fungus extracts have been found in respiratory allergy sufferers.
The spores of the stand fungi are found in different concentrations. The spores of the Basidiomycetes occur in different regions in significant concentrations in the air (up to 60 % of the total amount of spores) and can be the cause of allergic, IgE-mediated respiratory diseases like bronchial asthma or allergic rhinitis. Known are inhaled IgE-mediated sensitizations against porcini in workers in vegetable extract or soup production.
Boletus mycosis can trigger contact allergic eczema via type IV sensitization or be the cause of a food allergy.
Fungal spores of shiitake and mushroom can be detected as triggers of exogenous allergic alveolitis. Occupational exogenous allergic alveolitis can occur in mushroom growers as a result of inhalation of compost dust from edible mushroom cultures.
Contact eczema on stand fungi occurs almost exclusively in patients with intensive contact with fungi. Individual cases of contact eczema in mushroom pickers, in mushroom cultivation and in botanists as well as aerogenic contact eczema caused by the spore content of storage rooms have been documented. The occurrence of haematogenic contact eczema due to the consumption of forest fungi is also described (porcini and chestnut boletus).
Food allergies to boletus mushrooms occur only rarely. In these cases, the porcini mushroom is the predominant cause of an IgE-mediated systemic reaction, and more rarely the mushroom. The symptoms ranged from generalized itching, abdominal pain and diarrhea to urticaria, asthma and anaphylaxis. The cooking process seems to have little effect on the allergenicity of edible wild mushrooms.