Causes

Mold

Choose a preferred language


What is mold?

Mold is a member of the fungus family. It's rarely killed by heat or cold exposure. Mold stays inactive (dormant) until a certain season, such as spring or fall, or when favorable environmental conditions appear. Then it grows and thrives.


Where does mold grow?

Mold lives in moist conditions where there is oxygen and material to feed on. Mold may be found both outdoors and indoors.

Outside, mold is most often found:

  • On dead or dying vegetation, such as rotting leaves and logs.

  • In moist, shady areas.

Inside, you may find mold in:

  • Damp basements and closets.

  • Bathrooms.

  • Food storage areas.

  • Refrigerators.

  • House plants.

  • Air conditioners and humidifiers.

  • Mattresses or upholstered furniture that is damp.

  • Garbage containers.


What is mold allergy?

Mold spores or fragments may be breathed in through the nose and into the lungs. In some people, they may cause allergic reactions or asthma.

There is no known relationship between an allergy to the mold Penicillium and an allergy to the antibiotic penicillin, which is made from the mold. Talk with your child's health care provider for more information.

© 2000-2026 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
Related Articles
Read article
Allergies
Allergen: Insect Stings

Detailed information on allergic reactions to insect bites and stings.

Read article
Allergies
First Aid: Allergic Reactions

Learn how to help when someone is having a limited or severe allergic reaction.

Read article
Allergies
Controlling Asthma Triggers: Irritants

Things that pollute the air at home, work, or outdoors may bother your lungs if you have asthma. These things are hard to stay away from. They include smoke, perfume, sprays, and car exhaust. These tips may help you stay away from them.

Read article
Allergies
Avoiding Latex

If you have a latex allergy, the best way to prevent symptoms is to avoid latex. Here are some tips on how to do this.