Health Effects of Mold

In its report entitled Damp Indoor Spaces and Health (2004), the Institute of Medicine (IOM), a component of the National Academies, as commissioned by the Centers for Disease Control (CDC), concluded that there was sufficient evidence of an association between the presence of mold and several respiratory health effects. These mold related respiratory conditions include upper respiratory symptoms (e.g., sneezing, runny or itchy nose, throat irritation), wheeze, cough and acute asthma symptoms and hypersensitivity pneumonitis, an immune-mediated lung disease that can progress to permanent loss of lung function.

Health Effects That May Be Caused by Inhaling Mold or Mold Spores

According to the US EPA, inhalation exposure to mold indoors can cause health effects in some people. Molds produce:

  • Allergens (substances that can cause allergic reactions)
  • Irritants
  • Potentially toxic substances or chemicals (mycotoxins)
  • Inhaling or touching mold or mold spores may cause allergic reactions in sensitive individuals. Mold does not have to be alive to cause an allergic reaction. Dead or alive, mold can cause allergic reactions in some people.

Allergic Reactions, Asthma Attacks, Irritant Effects

Allergic reactions to mold are common and can be immediate or delayed. Repeated or single exposure to mold, mold spores, or mold fragments may cause non-sensitive individuals to become sensitive to mold, and repeated exposure has the potential to increase sensitivity. Allergic responses include hay fever-like symptoms such as:

  • Headache
  • Sneezing
  • Runny nose
  • Red eyes
  • Skin rash (dermatitis)

Molds can cause asthma attacks in people with asthma who are allergic to mold. In addition, whether individuals are allergic to mold, molds can irritate:

  • Eyes
  • Skin
  • Nose
  • Throat
  • Lungs

Other Health Effects

Breathing in mold may also cause hypersensitivity pneumonitis, an uncommon disease that resembles bacterial pneumonia. In addition, mold exposure may result in opportunistic infections in persons whose immune systems are weakened or suppressed.

When mold grows indoors, the occupants of a building may begin to report odors and experience a variety of symptoms including:

  • Headaches
  • Difficulty breathing
  • Skin irritation
  • Allergic reactions
  • Aggravated asthma symptoms
  • These and other symptoms may be associated with exposure to mold. But all these symptoms may be caused by other exposures or conditions unrelated to mold growth. Therefore, it is important not to assume that, whenever any of these symptoms occurs, mold is the cause.