What is mold?
Molds are various types of fungi (singular = fungus) that grow in filaments and reproduce by forming spores that can travel through the air. The term mildew refers to some kinds of mold, particularly mold in the home with a white or grayish color or mold growing in shower stalls and bathrooms. Mold may grow indoors or outdoors and thrives in damp, warm, and humid environments. Mold exists in essentially any environment or season.
The most common types of household mold found indoors include Cladosporium, Penicillium, Alternaria, and Aspergillus. Stachybotrys chartarum (also known as Stachybotrys atra and sometimes referred to as "black mold") is a greenish-black indoor mold, although it is less common than the other types of mold found in homes. Black mold grows on household surfaces that have high cellulose content, such as wood, fiberboard, gypsum board, paper, dust, and lint. There are types of mold that can grow on substances as different as foods and carpet.
Molds reproduce by forming tiny spores that are not visible to the naked eye. Mold spores are very hardy and can survive under conditions in which mold cannot grow, such as in dry and harsh environments. These spores travel through outdoor and indoor air. When the mold spores in the air land on a surface where moisture is present, mold can then start to grow.
What are the health risks of mold exposure?
Molds produce irritating substances that may act as allergy causing substances (allergens) in sensitive individuals. Furthermore, some molds produce toxic substances known as mycotoxins, but mold itself is not poisonous or toxic. The term "toxic mold," therefore, refers to the fact that certain kinds of mold can produce mycotoxins. The conditions under which some molds produce toxins is not understood, and the presence of mold, even a mold that is capable of producing toxins, does not always imply that toxins are being produced or that a health risk or problem is present. Mold may not cause any health problems, or it may lead to allergy or other symptoms in people, including adults and children, who are sensitive to molds.
What are symptoms and signs of mold allergy?
Allergic reactions to mold are the most common health effects of mold and are therefore the greatest health risk related to mold. Allergic reactions may happen immediately or develop after a period following exposure. Both growing mold and mold spores may lead to allergic reactions. Symptoms and signs of mold allergy may include
redness of the eyes,
skin irritation, or rash.
Mold or mold spores may cause asthma attacks in people who have asthma and are allergic to mold. Even in some nonallergic individuals, mold can cause symptoms of irritation in the eyes, skin, and airways. For example, the "black mold" Stachybotrys, along with some other types of mold, produces toxins known as mycotoxins that can cause irritation of the skin and airways in susceptible individuals.
Sometimes, people may develop severe reactions to mold exposure. Symptoms of severe reactions, which are uncommon, include fever and difficulty breathing. People with compromised immune systems or patients with chronic lung disease can develop serious infections of the lungs due to molds.
It is not possible to predict the degree of severity of the health risks associated with mold in the home. Allergic individuals vary in their degree of susceptibility to mold, and any symptoms and health risks also depend upon the extent and exact type of mold that is present.
In 2004 guidelines update in 2009, the Institute of Medicine (IOM) reported there was sufficient evidence to link indoor exposure to mold with upper respiratory tract symptoms, cough, and wheezing in otherwise healthy people, although the report stated that was no evidence that mold causes medical conditions like asthma, bronchitis, or other respiratory conditions.
Mold also worsens asthma symptoms in people who have asthma. Mold was also reported to be linked to hypersensitivity pneumonitis in individuals susceptible to this immunologic condition. This uncommon disease is similar to pneumonia and can develop in susceptible individuals after brief or prolonged exposure to mold, but there has been no conclusive evidence to prove this relationship.