Fungal species produce Type I allergens. Common indoor/outdoor species such as Alternaria, Pen icillian, Aspgillus, and Cladosporium cause allergic repertory disease, especially asthma. Pencillian and Aspgillus are also well-known causes of Type III allergens. And in high concentrations, Type IV allergens, hypersensitivity pneumonitius, are seen. Inside airways, germination and mycelia growth occur most which release greater amounts of spores, hyphae, and fungal fragments. Because these are well adapt at airborne dispersal, these are the most harmful fungal issues.
More Information available at World Health Organization.