Mold is a type of fungus that can be found both outdoors and in homes or buildings. It thrives in dark, damp environments, so you’ll most likely find mold growing in your basement, bathroom, under a sink, or in the garden on a log or pile of fallen leaves.i, ii

The spores (or seeds) of mold are barely visible to the naked eye and travel easily through the air. While all of us regularly breathe in these spores, they can cause an allergic reaction in some people – and because mold can grow in so many different places, these mold allergies can occur at any time of the year.ii, iii

Luckily, allergy symptom relief is available. Learn more about mold allergy symptoms, causes, and treatment options below.


While mold allergy symptoms can occur year-round, they are most common from July to early in the fall, as outdoor molds mostly disappear during the winter. There are many different types of mold, however only a few can cause allergic reactions.iii

Certain molds are toxigenic, meaning they produce substances called ‘mycotoxins’ that can be hazardous.v Mold can be many different colours, and colour should not be used as an indicator of how dangerous a type of mold may be.

You may have heard the term ‘black mold’ and that it is a more dangerous form of mold, however this isn’t necessarily true. Rather, all types of mold (and the source of its production) should be removed, regardless of colour.v


Like other allergies, including pet dander or dust allergies , your immune system cells respond to mold spores (the allergen) by releasing substances that can cause allergy symptoms. These symptoms may include:ii, iii

  • Sneezing
  • Runny nose or nasal congestion
  • Itchy, watery eyes
  • Itchy skin around the mouth, nose and lips

In some cases, mold spores can also reach the lungs and trigger or aggravate asthma symptoms, such as wheezing, shortness of breath or chest tightness. In rare cases, mold can cause the development of a serious respiratory illness called allergic bronchopulmonary aspergillosis.iv As with asthma, symptoms of this illness may include severe wheezing, coughing and shortness of breath.

If you think you may have a mold allergy, speak to your doctor or an allergist for an official diagnosis.


If you suspect you have a mold allergy, in addition to speaking with a doctor or allergist, try making a note of the times when your symptoms occur over a two-week period, to help build up a picture of which type of mold (or molds) you might be allergic to. Once you know the cause of your symptoms, it is easier to avoid situations where you might come into contact with spores. You can also take steps to reduce your exposure to mold with these simple tips:iii

  • Reduce humidity in the home – mold loves moisture, so reducing humidity in the home (ideally to below 35%, but at least to below 50%) can help to control mold production. Dehumidifiers and air conditioners can help to bring humidity levels down.
  • Pay attention to mold spore counts – knowing when mold spore counts are high can help you to avoid outdoor activity where possible.
  • Filter the air – use a central air conditioner fit with a certified filter or, if you don’t have an air conditioner, improve air flow through your home by opening windows whenever possible.
  • Use a dust mask – if you’re gardening or disturbing plant or grass material, wear a dust mask to reduce your mold spore exposure.
  • Remove sources of dampness – these are often in areas of the house like the bathroom or basement. Be sure to reduce moisture where possible, such as by fixing any leaks that occur.
  • Keep away rainwater – clear your gutters to make sure rainwater drains away from your house to avoid leaks or dampness.


Mold is persistent and can be found anywhere, so no matter how much effort you make to reduce it, if you do have a mold allergy, you may still find yourself suffering with symptoms at any time.

Thankfully, an over-the-counter allergy relief medication like FLONASE Allergy Relief can help. FLONASE provides 24-hour non drowsy allergy symptom relief – including nasal congestion, sinus pain and pressure, itchy nose and throat plus sneezing, runny nose and itchy, watery eyes – by controlling several key inflammatory substances your body releases when you have an allergic reaction, helping to relieve the symptoms that make you uncomfortable. Although you may not be as familiar with using a nasal spray, FLONASE works directly at the source (your nose) where allergic reactions to airborne allergies start. By using FLONASE you can help stop them where they start.