Despite being defined more than 100 years ago; atmospheric molds have remained undervalued as an important aeroallergen in allergy testing. Of the estimated number of more than 1 million different fungal species, approximately 80 species have been linked with respiratory allergy. However, epidemiologic studies have suggested that the prevalence of allergies to molds is less than 3% in an allergic population. The genera of molds that cause allergy and allergy-related problems most often are Alternaria alternate, Cladosporium herbarum, Aspergillus fumigatus and Penicillium. The most frequent genera involved in pediatric allergy are Cladosporium species in northern Europe and Alternaria species in both the Mediterranean region and North America.
Clinical aspects of Molds in Allergy Testing:
The molds themselves usually cultivate in warm, damp, or humid conditions and are spread by releasing spores into the air. Individuals breathe in the mold spores and their immune system thereby triggers common symptoms like sneezing, itchy, watery eyes, runny nose, nasal congestion or itchy nose, mouth, and lips. Some people may have more intense reactions that could lead to the development and persistence of upper and lower respiratory infections as well as allergic disease such as asthma, asthma severity, and potentially fatal asthma-related disorders.
Diagnostic Variability of Molds in Allergy Testing:
Mold allergy is usually diagnosed through clinical symptoms in addition to positive specific IgE results to mold species and/or skin prick testing. Mold allergy is difficult to diagnose for several reasons: First, molds from outdoor environment may show no seasonal variability, making the patient’s history less reliable in clinic. Second, a single fungal species can produce more than 40 different proteins stimulating IgE production; consequently, distinguishing clinically relevant mold antigens is problematic. Finally, standardization of mold extracts is nearly impossible, and this leads to variability in the clinical lab; mold extracts tend to have low allergenic activity and fluctuate considerably from batch to batch. However, recent assay development using molecular cloning techniques has allowed companies to create a better panel of recombinant allergens for the diagnosis of mold allergy.
Components of Mold Allergans:
Alternaria is the most known and well-studied mold species associated with fungal allergy in the literature. To date, 16 allergens of Alternaria alternate have been discovered, many of which are enzymes such as Alt a 4 (disulfide isomerase), Alt a 6 (enolase) and Alt a MnSOD (Mn superoxide dismutase). Others have structural and regulatory functions (Alt a 5, Alt a 12, etc.). Finally, the function of some allergenic proteins e.g., Alt a 1, Alt a 2, etc. are still unknown. For other molds, many potent allergenic proteins have also been defined. For example, from Aspergillus, most of the allergens are proteases including Asp f 5, Asp f 10, Asp f 13, Asp f 15, and Asp f 18.
Controlling Molds to Reduce Allergies:
Control of mold growth is really governed by controlling water and limiting mold growth. Humidity should be between 30% and 50% for as long as possible and an air conditioner or dehumidifier would help to keep levels low. Bear in mind that humidity levels change over the course of a day with changes in the moisture in the air and the air temperature, so you will need to check the humidity levels more than once a day. Ideally, provide enough ventilation so that molds cannot accumulate and use exhaust fans which vent outside the home for the kitchen and bathroom. Also, attempt to fix any leaks in the home’s roof, walls, or plumbing so mold does not have moisture to grow.
As stated at the onset, atmospheric molds have remained undervalued as an important aeroallergen in allergy testing. However, with improvements in mold allergens and diagnostic testing, detection of molds may become a key area that will improve inhalant allergen testing.
Available tests on NOVEOS as of August 2021:
Whole Allergen extract:
M001 Penicillium notatum*
M002 Cladosporium herbarum*
M003 Aspergillus fumigatus
M005 Candida albicans*
M006 Alternaria alternata
M008 Setomelanomma rostrata*
M012 Aureobasidium pullulans*
M207 Aspergillus niger
Allergen Component:
M229 rAlt a 1, Alternaria
*Menu in development
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