Cladosporium is the genera most frequently encountered in both outdoor and indoor air. It is frequently found in elevated levels in water-damaged environments. Some species may be resistant to certain types of treated lumber. Cladosporium appears gray to black or very dark green and can have a powdery appearance. The genus Cladosporium includes over 30 species. The most common ones include Cladosporium elatum, Cladosporium herbarum, Cladosporium sphaerospermum, and Cladosporium cladosporioides.
 
Cladosporium is a common fungus that is a known and documented aero-allergen which is usually associated with plants, wood products, and leather goods; the spores are easily made airborne and as such are a common cause of respiratory problems; allergic reactions and can be an agent for hypersensitivity diseases; it is as a parasite in infections of the skin, soft tissues or nails and has been documented in cases of Blastomycosis, Candidiasis, Chromoblastomycosis, Histoplasmosis, Entomophthoramycocis, Phaeophphomycocis and Keratomycosis.
 
The findings suggest that fungal antigens from species found in homes are commonly associated with skin sensitization in an allergy clinic population with upper or lower respiratory allergy. No specific relationships were found, however, between the prevalence of fungal species in the home environment and the prevalence as skin-test allergens.