Toxic Mold Exposure

Molds (also spelled "moulds") are ubiquitous in the biosphere, and mold spores are a common component of household and workplace dust. However, when mold spores are present in unspecified quantities, they can present a health hazard to humans, potentially causing allergic reactions and when present in large quantities, other types of respiratory problems. Mold allergies have always been a serious problem for many people. Research in the field of environmental health has yielded tests such as the MELISA assay, which can identify whether a person is allergic to specific epitopes associated with any particular mold. If a person is found to be allergic, the remedies listed below are often helpful in reducing allergic reaction.

Some molds, called "toxigenic molds", produce mycotoxins, which in high enough doses, can be beneficial or detrimental to human health. A common mycotoxin known to the general population of most western societies is penicillin. Extreme exposure to very high levels of mycotoxins can lead to neurological problems and in some cases death; fortunately, such exposures rarely to never occur in normal exposure scenarios, even in residences with serious mold problems. Prolonged exposure, e.g. daily workplace exposure, can be particularly harmful. The health hazards produced by mold have been associated with sick building syndrome, but no validated studies have been able to demonstrate that normal indoor exposures to these common organisms pose a significant threat.

Health issues and symptoms

Some specific molds and/or their mycotoxins can exacerbate or cause illnesses, including allergenic or irritant effects, or infection.

Exposure to fungi in indoor air in some occupational settings may present a significant threat to health, but this has not been demonstrated with any confidence in residential environments.

Molds can be allergenic, causing irritations of eye, nose, throat, and lungs. In response to this, environmental health research has yielded tests such as the MELISA test, which can determine whether a person is allergic to a specific mold.

Molds may excrete liquids or low-volatility gases, but the concentrations are so low that frequently they cannot be detected even with sensitive analytical sampling techniques. Sometimes these by-products are detectable by odor, in which case they are referred to as "ergonomic odors" meaning the odors are detectable, but do not indicate toxicologically significant exposures.

It is thought[citation needed] that all molds may produce mycotoxins and thus all molds may be potentially toxic if large enough quantities are ingested, or the human becomes exposed to extreme quantities of mold. Mycotoxins are not produced all the time, but only under specific growing conditions. Mycotoxins are harmful or lethal to humans and animals only when exposure is high enough. Some of the most deadly chemicals on the planet are similarly harmless at the concentrations normally encountered in ambient air.

Mycotoxins can be found on the mold spore and mold fragments, and therefore they can also be found on the substrate upon which the mold grows. Routes of entry for these insults can include ingestion, dermal exposure and inhalation.

Dermatophytes are the parasitic fungi that cause skin infections such as athlete's foot and tinea cruris. Most dermataphyte fungi take the form of a mold, as opposed to a yeast, with appearance (when cultured) that is similar to other molds.

Opportunistic infection by molds such as Penicillium marneffei and Aspergillus fumigatus is a common cause of illness and death among immunocompromised people, including people with AIDS.

Environmental illnesses can be difficult for healthcare practitioners to diagnose. People living in houses contaminated with mold are often aware of the fact due to the appearance of molds.

Mold spores

Health problems associated with high levels of airborne mold spores include allergic reactions, asthma episodes, irritations of the eye, nose and throat, infections, sinus congestion, and other respiratory problems. When inhaled by an immunocompromised individual, some mold spores may begin to grow on living tissue, attaching to cells along the respiratory tract and causing further problems. Generally, when this occurs, the illness is an epiphenomenon and not the primary pathology.

A serious health threat from mold exposure for immunocompromised individuals is systemic fungal infection. Immunocompromised individuals exposed to high levels of mold, or individuals with chronic exposure may become infected. Sinuses and digestive tract infections are most common; lung and skin infections are also possible. Mycotoxins may or may not be produced by the invading mold.

The most common form of hypersensitivity is caused by the direct exposure to inhaled mold spores that can be dead or alive or hyphal fragments which can lead to allergic asthma or allergic rhinitis. The most common effects are rhinorrhea (runny nose), watery eyes, coughing and asthma attacks. Another form of hypersensitivity is hypersensitivity pneumonitis. This is usually the direct result of inhaled spores or fragments in an occupational setting. It is predicted that about 5% of people have some airway symptoms due to allergic reactions to molds in their lifetimes.

Mold-produced mycotoxins

Certain molds excrete toxic compounds called mycotoxins, usually only under specific environmental conditions. Certain mycotoxins can be harmful or lethal to humans and animals when exposure is high enough.

Some mycotoxins cause immune system responses that vary considerably, depending on the individual. The duration of exposure, the frequency of exposure and the concentration of the insult (exposure) are elements in triggering immune system response.

Originally, toxic effects from mold were thought to be the result of exposure to the mycotoxins of some mold species, such as Stachybotrys chartarum. However, studies are suggesting that the so-called toxic effects are actually the result of chronic activation of the immune system, leading to chronic inflammation. Studies indicate that up to 25% of the population have the genetic capability of experiencing chronic inflammation to mold exposure, but only 2% actually experience such symptoms. A 1993–94 case study based on cases of pulmonary hemorrhage in infants in Cleveland, Ohio originally concluded there was causal relationship between the exposure and the disease. The investigators revisited the cases and established that there was no link to the exposure to S. chartrum and the infants in their homes.

Causes, growing conditions, and remedies

Mold growth in buildings can lead to a variety of health issues. Various practices can be followed to mitigate mold issues in buildings, the most important of which is to reduce moisture levels that can facilitate mold growth. Removal of affected materials after the source of moisture has been reduced and/or eliminated may be necessary for remediation.