Purpose: Fungi have been known to be important aeroallergens for hundreds of years. Most studies have focused on total fungal concentration; however, the concentration of specific allergenic fungi may be more important on an individual basis.
Methods: Ten fungal allergic patients and 2 non-fungal allergic patients were enrolled. The patients with a decrease in physician or patient global assessment by more than 50% of their personal best were considered to have an exacerbation of allergic symptoms and to be in the active stage. Those who maintained their physician and patient global assessment scores at their personal best for more than 3 months were considered to be in the inactive stage. The concentrations of dominant fungi in the patients' houses and outdoors were measured by direct and viable counts at active and inactive stages.
Results: The exacerbation of allergic symptoms was not correlated with total fungal spore concentration or the indoor/outdoor ratio (I/O). Specific fungi, such as Cladosporium oxysporum (C. oxyspurum), C. cladosporioides, and Aspergillus niger (A. niger), were found to be significantly higher concentrations in the active stage than in the inactive stage. Presumed allergenic spore concentration threshold levels were 100 CFU/m³ for C. oxysporum, and 10 CFU/m³ for A. niger, Penicillium brevicompactum and Penicillium oxalicum.
Conclusions: The major factor causing exacerbation of allergic symptoms in established fungal allergic patients may be the spore concentration of specific allergenic fungi rather than the total fungal concentration. These results may be useful in making recommendations as regards environmental control for fungal allergic patients.
Keywords: Fungal allergy; I/O ratio; airborne fungal spore; household; spore count; threshold level.