7.2.1 What Do I Need to Know About Mold Allergy?

The term fungus is often used interchangeably with mold. The organisms in this kingdom were classified by their micro- and macroscopic appearance in the past, which was cumbersome given different stages/appearances during their life cycle. Nowadays genomic analysis is being used frequently to place fungi into taxonomic groupings. Kingdom Fungi can be divided into 1 subkingdom (Dikarya), 7 phyla, and 10 subphyla.

Ascomycota is a phylum within the subkingdom Dikarya; this group is often referred to as Sac fungi. Sac fungi are useful for making bread, cheese, and alcohol (baker’s and brewer’s yeast) and antibiotics (Penicillium). Three subphyla within Ascomycota include Saccharomycotina (yeasts and Candida), Taphrinomycotina (hyphal fungi and Pneumocystis), and Pezizomycotina (truffles and Trichophyton). Cladosporium, Penicillium, Fusarium, Curvularia, Helminthosporium, Bipolaris, Phoma, Epicoccum, and Aspergillus are members of Pezizomycotina family and recognized as allergenic in humans, and are often pathogenic to plants.

The Basidiomycota phylum, also within Dikarya, includes complex structural fungi such as mushrooms, puffballs, smuts, and rusts. It also includes the pathogenic yeast Cryptococcus.

The phylum Glomeromycota typically forms a symbiotic relationship with plant roots. Important genera include Mucor, Rhizomucor, and Rhizopus. The remaining six fungal phyla include Microsporidia, Blastocladiomycota, Zoopagomycotina, Kichxellomycotina, Entomophthoromycotina, and Mucoro-mycotina.

Clinicians should be aware that mold extracts, as well as cockroach, contain proteolytic enzymes that may degrade pollen antigens; therefore these agents should not be instilled into a common treatment vial. Cross-reactivity of molds is very complex and unpredictable, although it is known that Alternaria and Cladosporium cross-react. General recommendations for allergy skin testing panels tend to include Alternaria, Aspergillus, Cladosporium, Helminthosporium, and Penicillium.