Mold and Allergies

By: Karen Serrano, MD

Molds can cause allergy symptoms throughout the year. They can be present indoors or outdoors. They exist anywhere there is moisture, oxygen, and other elements they need to grow.

Outdoor molds can be found almost everywhere, especially in areas where there is soil, vegetation, or rotting wood. Shady, moist areas with fallen leaves are excellent places for mold. There are also mold seasons. Outdoor mold spores appear after the so-called spring thaw or when the weather starts to get warm. In warmer areas, they peak in mid-summer. In cooler areas, mold counts don't peak until October. Check with your local Health Department for more information about peak mold seasons in your area.


Indoor molds, however, occur year-round and are found in damp and dark areas, including:

  • air conditioners
  • attics
  • barns or stables
  • basements
  • bathrooms
  • carpets
  • crawl spaces
  • garages
  • garbage containers
  • greenhouses
  • houseplants
  • mattresses
  • old foam rubber pillows
  • places with standing water
  • pool houses
  • refrigerators
  • summer cabins that have been closed up
  • under sinks
  • upholstery