Indoor Allergies Causes, Symptoms, and Testing

What are indoor allergies?

Indoor allergies are often the cause of year-round symptoms, which is why they are sometimes referred to as year-round allergies or perennial allergies. If you are always sniffling and sneezing, you may think of your home as a place to escape and recuperate from what seems like an endless cold. But there are allergens found inside the home that may actually be the cause of symptoms. Worldwide, sensitization to foreign proteins (e.g., animal dander and mold) in the environment is present in up to 40 percent of the population.1

Exposure Reduction: Tips for Managing the Most Common Allergies

Common Indoor Allergens

Click on an indoor allergen to learn more about the specific allergy, including where it can be found, common symptoms, testing information, allergy management, and symptom relief.  


Dust Mites

Are you a healthcare provider looking for a comprehensive list of year-round allergens and associated symptoms? 

Explore our fact sheets, an easily sharable, patient-friendly resource that includes cross reactivities, component names, and management plans.

Indoor Allergy Symptoms

Indoor allergy symptoms are similar to most other allergies and include:

  • Itchy, stuffy nose 
  • Runny nose
  • Sneezing
  • Itchy, watery, swollen, bloodshot eyes 
  • Scratchy, swollen throat 
  • Coughing
  • Wheezing
  • Tightness in the chest

Is it year-round allergies or something else?

If you are suffering from symptoms throughout the year, you may not be able to find relief until you receive an accurate diagnosis. Even allergies to indoor triggers can appear seasonal in nature, since the allergen levels will vary with environmental conditions such as temperature and humidity. 

A blood test can help detect sensitization to hundreds of potential allergic triggers, including pollen, mold, food, and animal dander. Learn more about blood testing.

For a better consultation with a healthcare provider, it’s helpful to keep track of the types of symptoms experienced and when they occur.

Frequently Asked Questions About Indoor Allergies

There are several ways to help manage year-round allergy symptoms. Exposure reduction can be employed to help manage systems for the following allergens:2,3 

Animal Dander

  • Confine the pet to a room with a polished floor and furniture you can wipe down. 
  • Restrict the animal from the bedroom and keep it off the furniture. 
  • Use high-efficiency particulate air (HEPA) filters and vacuum cleaners. 
  • Wash your pet weekly in warm water and soap. 
  • Consider rehoming the pet or keeping it outdoors. 

Dust Mites

  • Encase mattresses, pillows, and box springs in allergen-proof coverings. 
  • Wash bedding weekly in water 130 F (54 C) or more.  
  • Vacuum and reduce clutter in the home. 
  • Wear an appropriate mask while cleaning and avoid the area for 20 minutes thereafter. 
  • Change furnace and air conditioner filters. 
  • Use a dehumidifier to reduce the humidity in your home.   


  • Vacuum and sweep floors after meals, and immediately do the dishes.  
  • Keep food and garbage in closed containers; take out the garbage regularly. 
  • Locate and remove cockroach hiding places and food sources.  
  • Fix leaky faucets and pipes to remove an accessible water source for roaches.  
  • Remove clutter. Don’t store paper bags, newspapers, or cardboard boxes in your home. 
  • Place bait traps or call a professional exterminator to eliminate cockroaches. 
  • Seal plumbing openings, cracks, and crevices.  

Indoor Mold

  • Identify and clean moldy areas with fungicide or bleach. 
  • Use a dehumidifier to reduce humidity in your home. 
  • Fix water leaks. 
  • Clean furnace filters, the refrigerator, and the dehumidifier (clean drip pans with bleach). 
  • Dry clothes thoroughly before storing.   


  • Seal holes and cracks from the home to the outside. 
  • Seal passages through interior floors, walls, the ceiling, and gaps between the bottom of cabinetry or built-in furniture and the floor. 
  • Keep bushes and trees at least three feet from the home. 
  • Ensure trash is stored in secure containers. 
  • Store food in rodent-proof containers. 

If you experience symptoms such as watery eyes and sneezing after touching or being around a cat, dog, or horse, you may have an animal dander allergy. A combination of skin, fur, and saliva, animal dander is extremely lightweight and can stay in the air for hours. Because of this, it can cause symptoms long after the animal has left the room. Dander can also land and stay on furniture, carpets, mattresses, upholstery, and clothing. In fact, people who have pets can unknowingly carry dander with them everywhere they go, including school or work.

An allergy to animals in general, and cats and dogs in particular, is a risk factor for developing asthma and allergic rhinitis.4

Insects, such as cockroaches, have proteins in their body parts, saliva, and waste that can set off allergy symptoms and asthma, even after they are dead. Symptoms may be worse during or after cleaning because vacuuming, sweeping, and dusting can kick up the reaction-causing protein into the air, making it easier to inhale. Insect allergy symptoms are similar to hay fever or pollen allergy symptoms but continue beyond the spring or fall seasons. 

Indoor Allergy Testing and Management 

To properly manage and treat year-round allergies, it’s important to understand exactly what is causing symptoms. The first step is talking to a healthcare provider about allergy testing options

Healthcare providers are encouraged to use test results and a person’s medical history to devise a comprehensive, yet targeted, environmental remediation strategy limiting exposure to known allergens. The treatment of year-round allergies includes the use of three different types of intervention:3,5

  1. Allergen avoidance and environmental control measures
  2. Pharmacological management
  3. Immunotherapy

A blood test—together with an allergy-focused medical history—may help identify underlying allergen triggers. 

A blood test—together with an allergy-focused medical history—may help identify underlying allergen triggers. 

In the treatment of year-round allergies, the most effective control measures include patient education, use of HEPA filters, integrated pest management, thorough cleaning, and continuation of these practices.3

Practice Parameters and Guidelines for Indoor Allergies

Practice parameters have been developed to classify and manage treatment of year-round allergies, and guideline-directed management has been shown to improve disease control.3 Allergic rhinitis has also been found to be triggered by some year-round allergens.
Across these practice parameters and guidelines, allergen avoidance is also a primary method of controlling comorbid conditions (e.g., asthma) that are initiated or exacerbated by exposure to indoor allergens.3

Tools for Understanding Allergies


Track allergy symptoms and prepare for a visit with a healthcare provider.

Learn about specific allergens, including common symptoms, management, and relief. 

Are you a healthcare provider? Get comprehensive information on hundreds of whole allergens and allergen components.

Related Content

Want to learn more about seasonal allergies? Explore a range of topics.

  1. American College of Allergy, Asthma & Immunology [Internet]. Arlington Heights, IL: American College of Allergy, Asthma & Immunology; 2021. Available from: 
  2. Discover the connection: Reduce Exposure to Your Allergic Triggers. Thermo Fisher Scientific Inc. 2018. 
  3. Wright LS, Phipatanakul W. Environmental Remediation in the Treatment of Allergy and Asthma: Latest Updates. Curr Allergy Asthma Rep. 2014 March;14(3): 419.
  4. Nicholas CE, et al, Dog allergen levels in homes with hypoallergenic compared with nonhypoallergenic dogs. Am J Rhinol Allergy. 2011 Jul-Aug; 25(4): 252–256. 
  5. Scadding GK. Optimal management of allergic rhinitis. Arch Dis Child. 2015;100:576–582.