Condition content was medically reviewed by an AllerVie Health physician in Oct. 2022.

About Mold Allergies

Exposure more often occurs from inhaling or contact with mold spores, which can trigger allergic symptoms such as coughing, sneezing, runny/stuffy nose, or itchy eyes. 

If your reaction is more severe or if you are exposed to high-levels of mold, you may even find it hard to breathe as your airways spasm and tighten. There are many types of molds, but only a few cause mold allergies.

Although molds can grow year-round, peak-season is late summer to early fall when temperatures are warmer and humidity levels are higher.


Outdoor Mold

Mold thrives in outdoor environments and can be seen growing on a variety of organic matter, including rotting wood, dead leaves, compost, and even grains and grasses. 


Indoor Mold

Indoors, mold thrives in humid areas including basements, bathrooms, kitchens, laundry rooms, and carpeted areas. Given the correct conditions, mold can quickly spread across a house, but there are measures to prevent this. 

What Are the Symptoms of Mold Allergy?

The symptoms of mold allergy are very similar to the symptoms of pollen allergy. Symptoms of mold allergy include:

  • Sneezing
  • Runny or stuffy nose
  • Cough and postnasal drip
  • Wheezing, shortness of breath
  • Itchy eyes, nose and throat
  • Watery eyes
  • Dry, scaly skin

For those with asthma, mold allergy can trigger asthma exacerbations with symptoms such as:

  • Difficulty breathing
  • Chest tightness or pain
  • Wheezing
  • Shortness of breath
Handyman cleaning outdoor mold from vinyl siding on an exterior wall of a house with a pressure washer

What Causes Mold Allergy?

There are many types of molds, but only certain ones cause allergies. If you have an allergy to one type of mold you won’t necessarily be allergic to another.

Molds that most often trigger allergies include Alternaria, Aspergillus, Cladosporium, and Penicillium.

  • Alternaria is a type of fungi found in soil, on plants, rotten wood, bricks, canvas, iron, compost, and bird nests.
  • Aspergillus is a common mold that lives indoors and outdoors. Most people breathe it in everyday without any reaction.
  • Cladospirium is a primarily indoor mold that can be found in areas with humidity, moisture, and water damage.
  • Penicillium is a common indoor mold that produces penicillin; however, you can be allergic to Penicillium and not have an allergy to the penicillin medication.

Risk Factors for Mold Allergies

Family history of allergies

Work that exposes you to mold.

Higher-risk jobs include farming, dairy work, logging, baking, millwork, carpentry, greenhouse work, winemaking and furniture repair

Living and/or sleeping in damp environments

indoor humidity higher than 50% can increase mold levels

Testing for Mold Allergies

We have allergy specialists who can check for mold sensitivities. You’ll need to describe the symptoms you’ve been having and when you first noticed them. Both your job and home settings should be described in detail.

The allergist will perform diagnostic testing, such as a skin prick test or a blood allergy test, to determine if you are allergic to mold. Depending on the outcomes, more testing may be recommended and a treatment plan will be developed.

Preventing Exposure to Mold

Controlling and preventing exposure to mold are the easiest and most effective ways to address mold allergies. 

Steps to control mold in your home include:

  • Quickly clean up any spills or leaks to prevent mold from growing.
  • Use dehumidifiers or exhaust fans — or crack open a window — to help reduce moisture and humidity in bathrooms, the basement or other rooms in your home.
  • Regularly clean garbage cans and refrigerator drip pans.
  • Regularly clear your gutters, and ensure that drainage flows away from your home’s foundation.
  • Take steps to keep the humidity in your house low (<50%)
  • Make sure your house is properly ventilated, especially the bathrooms and kitchen. 
  • Repair and seal any water leaks immediately.
  • Minimize houseplants
  • Use a sump pump in the basement if it is prone to flooding
  • Ventilate clothes dryer to the outside
  • Use air conditioning in the summer with high humidity, and heat all rooms in the winter, including outside wall closets

Avoiding Outdoor Mold

  • Check your local mold counts before engaging in outdoor activities. 
  • Stay indoors as much as possible when mold counts are high. 
  • Keep in mind that damp forests, fallen leaves, and other damp places are where mold likes to hide out. 
  • Avoid exposure to uncut fields and raking leaves. 
  • Take a shower after being outside and launder clothes worn while outside

How to Remove Mold Indoors

If you have water damage/visible moldy areas (beyond the normal mildew sometimes seen on window sills, bathroom/kitchen grout, etc.) it is recommended that you consult with a professional remediation service.

The EPA provides guidelines for mold cleanup in your home.