Health Concerns

Mold and Health Concerns

Mold is ubiquitous to our planet and is found in every ecological niche. Thriving in moist or wet environments, it can grow on almost any surface including cloth, carpet, leather, wood, sheet rock, insulation, and even on food.

Mold reproduces spores, which can cause health problems in humans, when they are exposed to it. Exposure can be in the form of direct contact on surfaces, through the air, or if they are aerosolized. Mold-related health issues can include allergies, infections, irritation (mucous membrane and sensory), and toxicity.


Allergies are the most common response to mold. Symptoms develop when a person’s skin or respiratory system is exposed to mold or mold byproducts. Reactions can range from mild, transitory responses, to severe, chronic illnesses. Allergic rhinitis is the single most common chronic disease experienced by humans (1 in 5 Americans) while allergy-related sinusitis (14% of the population) and allergically-related asthma (10%-12% of Americans) are close behind. Other allergic reactions include allergic dermatitis (9%), chronic allergic bronchopulmonar, aspergillosis, and chronic hypersensitivity pneumonitis.


Infections are a common result of mold exposure. A number of indoor aspergillus species are known as pathogens, and can be a source of nosocomial infections, that affects the skin, eyes, lungs, or other organs and systems.

Mucous Membrane and Trigeminal Nerve Irritation

Some fungal species can produce alcohols or aldehydes and acidic molecules. The compounds can irritate the mucous membrane of the eyes and respiratory system. Other compounds can release the highly toxic arsine gas (from arsenic) into the atmosphere.

In addition to irritating the mucous membrane, volatile fungal compounds may impact the “common chemical sense,” which senses and responds to pungency. The nerve that responds to pungency initiates avoidance reactions, including breath holding, discomfort, parenthesis, or odd sensations (itching, burning, and skin crawling). Other responses might occur, such as mucous membrane swelling, constriction of the respiratory smooth muscle, dilation of surface blood vessels, disorientation, diminished reflex time, or dizziness.

Adverse Reaction to Odor

Some individuals experience adverse effects from odors produced by molds. Asthmatics are a particular group of the population that can respond negatively to odors. Some symptoms of mold-produced odors can be headaches, nasal stuffiness, nausea, or even vomiting.


The toxic effects from mold are actually associated with exposure to toxins on the surface of the mold, in the air, or through skin contact. Studies have shown that these (organisms that are toxic to higher plants and animals, including humans) can produce upper respiratory tract irritation and rashes. When the mold was substantially reduced, the symptoms disappeared.
Not all mold produce mycotoxins, but numerous species do. It should also be known that not all molds have been tested for toxins. The conditions for toxin production vary with seasonal cycles and substrate on which the mold grows.

The following summary of toxins and their targets is adapted from Smith and Moss (1985), with a few additions from more recent literature. This list gives an idea of possible reactions to mycotoxin exposure.

Vascular systems – can result in increased vascular fragility, hemorrhaging in body tissues or in the lungs.
Digestive system – can result in diarrhea, vomiting, intestinal hemorrhaging, and liver problems.
Respiratory system – can result in respiratory pain or bleeding in the lungs.
Nervous system – can result in tremors, lack of coordination, depression, and headaches.
Cutaneous system – can result in rashes, burning sensations, sloughing of the skin, or photosensitization.
Urinary system – can result in nephrotoxicity.
Reproductive system – can result in infertility or changes in the reproductive cycles.
Immune system – can result in changes or suppression.

You can find more about the toxicity of molds on the Center for Disease, Control and Prevention, or contact us and we can provide you with additional research.