Mold Exposure Symptoms, Allergies and Health Indoors

mold exposure symptoms

When moisture problems occur and mold growth results, building occupants may start to develop mold exposure symptoms. They may report odors, allergies or a variety of other health problems indoors. Mold exposure symptoms can include breathing difficulties, headaches, allergic reactions, skin rashes, and aggravated asthma symptoms, among many others. The safety of building occupants and also of workers performing the mold repairs (remediation) must always be taken into consideration.

The possible consequences of mold exposure may be greater for certain individuals than for others. For instance, bee stings pose a great risk for persons with a history of allergic reactions. However, others with bee stings may only suffer a minor irritation. The possibility of different levels of mold exposure sensitivity must always be considered when evaluating potential health risks.

All molds have the potential to cause health effects. Through the production of allergens, irritants, and perhaps toxins, molds can affect the wellbeing of building occupants and remediation workers. The reactions of the individuals exposed to mold and the severity of the mold exposure symptoms may vary. This is based on the types and concentrations of molds present, the duration of the exposure and the sensitivity and age of the individual(s) exposed.

There are certain groups that are commonly considered to be higher-risk populations for mold exposure. Persons with compromised immune systems, the elderly, young children, people with respiratory sensitivities and those with chronic exposure may all be at greater risk for developing symptoms than healthy adults or those with limited exposure.

Mold Exposure Symptoms Indoors

Exposure to mold can include the following types of reactions:

Mold exposure symptoms and their reactions are common. They can be set off by breathing spores or by skin contact with mold when the person has an increased level of sensitivity. Reactions can be immediate or delayed. Symptoms may include fever, sneezing, runny nose, and/or burning eyes. In extreme cases, life-threatening reactions such as anaphylactic shock have been reported. Repeated or even a single exposure to a sufficiently high concentration of mold may cause a previously non-sensitive individual to become sensitive. The more prolonged the exposure, the greater the risk of developing allergic sensitivity. Mold spores and spore and cell fragments may be capable of producing allergic reactions whether the molds are dead or alive (viable).

Asthma attacks have been known to be triggered by mold exposure. The irritants produced by molds may also worsen asthma in non-allergic (non-sensitized) people.

A chronic disease that resembles pneumonia called Hypersensitivity Pneumonitis may develop during either a short, acute exposure or as a result of chronic exposure to low or moderate levels of mold.

Persons with compromised immune systems may fall prey to Opportunistic Infections as a result of their body’s inability to protect itself against common mold exposures. Because of their compromised immune system, they are much more susceptible to these types of mold infections. Aspergillus fumigatus and Trichoderma, among many others, have been identified as species of molds that can cause opportunistic infections in immune-compromised adults and children. It should be noted that massive and/or extended exposures are more likely to lead to infection, perhaps even in healthy individuals.

It must be noted that molds are found in the outside air almost all the time. Most people do not have extreme reactions to exposures to mold in the outside air. This leads some to erroneously assume that mold exposure in buildings should be of no greater concern than those outside.

The difference is that mold exposure inside is generally both quantitatively and qualitatively different.

The indoor environment is quite different from those outside. Thus, certain molds have a competitive advantage, with molds that are often rare outside often dominant inside. Unfortunately, many of the types of molds that often grow inside buildings are “species of concern.” These are molds that have been associated with health effects in humans.

When mold spores grow and are released into the air outside, they disperse. Mold exposure for people in the vicinity are limited. But when molds grow inside buildings, their released spores and other particles tend to be trapped and thus are able to build up to concentrations rarely if ever seen outside.

For example, in Florida total mold spore concentrations outside are often in the range of 500 to 5000 per cubic meter of air, m3. Although outside concentrations may often go much higher, 50,000/m3 or more, such concentrations tend to be transient. By contrast, concentrations in moldy buildings may sometimes be as high as 500,000/m3 or even considerably higher. To make matters worse, these concentrations do not disperse and may remain at such high levels for long periods, exposing occupants to doses (exposure x duration) that would never be found outside.


IET’s mold inspection services are provided in the entire Tampa Bay area and Florida.  If in need of any of our indoor environmental services, please contact us today.


Next Article: Mold Growth and Mold Remediation in Buildings


  1. Julia says:

    I suffer from severe mold related allergic reactions. Effective cleaning of all rooms in the house is an absolute must, but getting a highly rated air purifier I would say is also required.

  2. Rena Smith says:

    I am totally agreed with Julia. One of cousin recently suffering from mold allergic reaction and my mum just bought him an air purifier with hepa filter. After one week, he feels a lot better.

  3. IET says:

    I agree with both Julia and Rena. High-efficiency filtration of the HVAC system, using deep-pleat filter systems located immediately before the air handler such as those made by Aprilaire, is one of the most effective ways to reduce particles in the air of the home. IET is a dealer for IQAir air purifiers, which we think are among the best available.


    Tim Toburen
    Environmental Consultant

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