Chest Discomfort or Pain

Causes of indoor allergies

Fact Checked

Many individuals end up with allergy attacks if they spend time outdoors, but there are also allergens inside the house that can trigger indoor allergies among sensitive individuals.


One of the common causes of indoor allergies is mold. It is important to note that mold is abundant most of the year indoors. They thrive in moist and warm settings such as in kitchens, bathrooms or on shower curtains, door seals of refrigerators and window frames.

In some cases, mold is also present in beds. Take note that the water reservoirs of dehumidifiers can also serve as a breeding place for mold. The spores that they produce are oftentimes hidden below wallpaper and present in the soil of plants placed inside the house.

The indications of mold allergy are reduced during dry, warm weather and can be quite troublesome during cloudy, damp and misty days.

House dust mites

Indoor allergies
One of the common causes of indoor allergies is mold. It is important to note that mold is abundant most of the year indoors.

Dust mites are present in most houses and the most common allergen capable of triggering indoor allergies among asthmatic children. Dust mites could not survive in extremely cold or dry conditions and need food, warmth and water by absorbing moisture via their skin.

The bedroom is the ideal place for them to thrive, especially beds due to the supply of dead skin cells readily available that serves as their food along with warmth, sweat and breath. Dust mites can also find skin cells and other proteins to eat in upholstered furniture, carpets, stuffed toys and fabrics.

The allergen responsible for triggering a response from the immune system is mainly found in their droppings that are quite dry and spread in the air as fine particles. Since these become airborne, they are readily inhaled into the airways and lungs. These particles settle into pillows, duvets, mattresses, carpets and upholstery.

Animal allergens

It is important to note that animal allergens are also considered as common causes for indoor allergies. The allergen responsible for an allergic reaction is found in the skin, saliva and urine of animals.

When a pet grooms, the allergen coats the fur, skin or feathers and spreads by shedding skin cells as well as licking. The size of the allergen is quite small and readily becomes airborne and breathed in which results to respiratory issues as well as sneezing, itchy eyes and irritation of the skin.

Allergens from cats are found on the walls and ceilings for several months or even years, after the animal has left the house. This can be found in shoes and clothes of cat owners, thus it rapidly spreads. Take note that other birds including parrots are also another cause of indoor allergies but the feathers are rarely the cause of the reactions. The dust present in feather pillows might be considered as the cause of the symptoms since mold and dust mites can grow in them.

Small domestic pets such as hamsters and guinea pigs can spread allergens by urinating in their bedding. The allergen can become airborne once they scurry around the cage. It is not advisable to keep these pets in the bedroom if an individual is allergic.


Leave a Comment

Your email address will not be published. Required fields are marked *

The information posted on this page is for educational purposes only.
If you need medical advice or help with a diagnosis contact a medical professional

  • All content is reviewed by a medical professional and / sourced to ensure as much factual accuracy as possible.

  • We have strict sourcing guidelines and only link to reputable websites, academic research institutions and medical articles.

  • If you feel that any of our content is inaccurate, out-of-date, or otherwise questionable, please contact us through our contact us page.