When mold growth occurs in a building, occupants may begin to report both odors and a variety of health-related issues, such as headaches, difficulty breathing, skin irritation, allergic reactions, and aggravation of asthma symptoms. All of these issues may potentially be associated with mold exposure.
All molds have the potential to cause negative health effects. Molds produce allergens, irritants, and in some cases, toxins that may cause reactions in humans. The types and severity of symptoms depend, in part, on the types of mold present, the extent of an individual’s exposure, the ages of the individuals, and their existing sensitivities or allergies.
Specific reactions to mold growth can include the following:
Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals. Allergic reactions to mold are common; these reactions may be either immediate or delayed. Allergic responses include hay fever-type symptoms, such as sneezing, runny nose, red eyes, and skin rash (dermatitis). Mold spores and fragments can produce allergic reactions in sensitive individuals regardless of whether the mold is dead or alive. Repeated or dingle exposure to mold or mold spores may cause previously non-sensitive individuals to become sensitive. Repeated exposure has the potential to increase sensitivity.
Molds can trigger asthma attacks in persons who are allergic (sensitized) to molds. The irritants produced by molds may also worsen asthma in non-allergic (non-sensitized) people.
Hypersensitivity pneumonitis may develop following either short-term (acute) or long-term (chronic) exposure to molds. The disease resembles bacterial pneumonia and is uncommon.
Mold exposure can cause irritation of the eyes, skin, nose, throat, and lungs, and sometimes may create a burning sensation in these areas
People with weakened immune systems (i.e., immune compromised or immune-suppressed individuals) may be more vulnerable to infections by molds (as well as more vulnerable than healthy persons to mold toxins). Aspergillus fumigatus, for example, has been known to infect the lungs of immune-compromised individuals. These individuals inhale the mold spores which then begin growing in their lungs. Trichoderma has also been known to infect immune-compromised children. Healthy individuals are usually not vulnerable to opportunistic infections from airborne mold exposure. However, molds can cause common skin diseases such as athlete’s foot, as well as other disorders such as yeast infections.
Molds can produce toxic substances called mycotoxins. Some mycotoxins cling to the surfaces of mold spores; others may be found within the spores. More than 200 mycotoxins have been identified from common molds, and many more remain to be identified. Some of the molds that are known to produce mycotoxins are commonly found in moisture-damaged buildings. Exposure pathways for mycotoxins can include inhalation, ingestion, or skin contact. Although some mycotoxins are well known to affect humans, little information is available for many others.
Aflatoxin B1 is perhaps the most well-known and studied mycotoxin. It can be produced by the molds Aspergillus flavis and Aspergillus parasiticus, and is one of the most potent carcinogens known. Ingestion of aflatoxin B1 can cause liver cancer. There is also some evidence that inhalation of aflatoxin B1 can cause lung cancer. Aflatoxin B1 has been found on contaminated grains, peanuts, and other human or animal foodstuffs. However, Aspergillus flavus and Aspergillus parasiticus are not commonly found on building materials or in indoor environments.
Much of the information on the health effects of inhalation of mycotoxins on humans comes from studies done in the workplace, along with some case studies and case reports.
Many symptoms and human health effects attributed to inhalation of mycotoxins have been reported, including: mucous membrane irritation, skin rash, nausea, immune system suppression, acute or chronic liver damage, acute or chronic central nervous system damage, endocrine effects, and cancer. More studies are needed to get a clearer picture of the health effects related to most mycotoxins. However, it is definitely prudent to avoid exposure to molds and mycotoxins.
Some molds can produce several toxins, and some molds produce mycotoxins only under certain environmental conditions. The presence of mold in a building does not necessarily mean that mycotoxins are present or that they are present in large quantities.
Note: Information on ingestion exposure, for both humans and animals, is more abundant. A wide range of health effects has been reported following ingestion of moldy foods including liver damage, nervous system damage, and immunological effects.
Microbial Volatile Organic Compounds (mVOCs)
Some compounds produced by molds are volatile and are released directly into the air. These are known as Microbial Volatile Organic Compounds (MVOCs). These compounds often have strong and/or unpleasant odors, and may be the source of odors associated with molds. Exposure to MVOCs from molds has been linked to symptoms such as headaches, nasal irritation, dizziness, fatigue, and nausea. Research on MVOCs is still in the early phase.
or Fungal Cell Wall Components (also known as β-(1->)-D-Glucans)
Glucans are small pieces of the cell walls of molds which may cause inflammatory lung and airway reactions. Glucans can affect the immune system when inhaled. Exposure to very high levels of glucans or dust mixtures including glucans may cause a flu-like illness known as Organic Dust Toxic Syndrome (ODTS). This illness has been primarily noted in agricultural and manufacturing settings.
Mold spores are microscopic, and are naturally present in both indoor and outdoor air. Molds reproduce by means of spores. Some molds have spores that are easily dislodged and will drift into the air upon disturbance. Other molds have sticky spores that will cling to surfaces and are dislodged by brushing against them or through other direct contact. Spores may remain able to grow for years after they are produced. Regardless of whether the spores are alive, however, the allergens in and on them may remain allergenic for years.
Key Mold Indicators
Checklist which summarizes some indicators of mold on both your home and body. It is intended as an aid to help you determine whether you should contact us.
Dark spots on my wall or ceiling
Strong musty smell in my home
Recently experienced a water leak
Unexplainable health problems
Burning sensation in eyes, skin, nose or throat
Unexplainable worsening of asthma symptoms