Know Your Allergy Triggers

Medically Reviewed by Jabeen Begum, MD on October 31, 2023
11 min read

Many things can trigger allergies. The most common are pollen, dust mites, mold, animal dander, insect stings, latex, and certain food and medications.

 If it's hard to tell what's causing your allergies, or if you're finding it difficult to manage them on your own, see a doctor about getting allergy tests. The tests will help pinpoint exactly what your triggers are. In the meantime, try to keep notes on your symptoms -- when they start, how long they last, and whatever seems to bring them on, and tell your doctor about them.

Here are things you need to know about the eight most common culprits.



1. Pollen

The air is filled with pollen from fresh, growing things like grass, trees, and weeds in the spring and summer, which can cause allergy symptoms. In some people, ragweed in the fall may trigger allergies. Pollen allergy symptoms include: 

  • Fatigue. You may not be sleeping well because your stuffy nose makes it hard to breathe at night.
  • Itchy eyes, nose, or roof of your mouth
  • Runny, stuffy nose
  • Sneezing
  • Watery eyes, redness, or swelling

 To manage a pollen allergy:

  • Ask your doctor about taking medications like decongestants or antihistamines to relieve a blocked or stuffy nose.
  • Keep your car and home windows closed during “high pollen” times.
  • Wear a hat outside to keep pollen out of your hair, and wash your hands and face when you get inside.

2. Dust mites

These critters are so tiny you can’t see them without a microscope. Symptoms of dust mite allergy are similar to those caused by a pollen allergy, but they often happen year-round instead of during certain seasons.

Treatments include medications such as steroid nasal sprays, antihistamines, and decongestants.


  • Put dust mite covers over mattresses, pillows, and box springs.
  • Use hypoallergenic pillows.
  • Wash sheets weekly in hot water.
  • Keep all areas of your home, especially the bedroom, free of stuff that collects dust, like stuffed animals, curtains, and carpet.

3. Mold

Molds are tiny fungi with spores that float in the air like pollen. They grow in damp areas like basements or bathrooms and piles of leaves or grass.

Mold allergy symptoms are similar to those of pollen and dust mite allergies. They include sneezing, congestion, itchy and watery eyes, runny nose, and coughing.

Treatment is similar to that for dust mite and pollen allergies. To manage mold allergy, you can also:

  • Avoid mold and get rid of things that help it grow.
  • Repair any water damage or leaks in your home.
  • Get rid of indoor plants because their soil can hold mold.
  • Use a dehumidifier to keep your home dry.
  • Wear a mask if you're raking leaves in the fall.

4. Animal dander and cockroaches

Dander are flecks of skin shed by cats, dogs, and birds. Dander can trigger allergies. You might also react to the proteins from oil glands in an animal's skin or from an animal's saliva.

It may take 2 or more years to develop an allergy like this. Once you have symptoms, though, they may last until you don’t come into contact with the animal anymore. If you don’t have pets, it might be cockroaches that you’re allergic to.

Animal dander allergy symptoms include sneezing, congestion, and itchy and watery eyes.

 To manage animal dander allergy:

  • Avoid the animals that cause your allergies when possible. If you’re allergic to your pet, ask your doctor if there’s anything you can do that may help limit contact with allergens, like keeping it off your bed and couches.
  • Bathe your pet every week. Get someone who isn’t allergic to do it if you can.
  • You can also take medications like antihistamines, decongestants, and nasal steroids to help with your allergy. Allergy shots, which are injections that help stop or manage allergy symptoms, might also help.
  • If you have cockroach allergies, keep trash in closed containers and regularly take it out of your home. Consider getting an exterminator.

5. Insect sting

Ouch! Something stung you, and now you’re having a bad reaction to it.

Insects that cause allergic reactions include bees, fire ants, yellow jackets, hornets, and wasps.

If you get stung by an insect, you might have pain, swelling, redness, and heat around the sting site. Those allergy symptoms can last for a few days.

It’s rare, but some people get a dangerous, full-body reaction called anaphylaxis, which needs emergency treatment. Symptoms of anaphylaxis include:

  • Trouble breathing
  • Becoming hoarse
  • Wheezing (a whistling sound when you breathe)
  • Swelling, especially around your face, eyelids, ears, mouth, hands, or feet
  • Belly cramps, nausea, vomiting, or diarrhea
  • Feeling dizzy or passing out

 To manage insect stings:

  • Avoid wearing brightly colored clothes and scented lotions or cosmetics, as they may attract insects to you.
  • Keep insecticide handy, wear shoes outdoors, and avoid outdoor garbage, honey, lemonade, and other foods at a picnic.
  • Talk to your doctor about allergy shots. They can help prevent anaphylaxis.

If you get stung:

  • Try to remove the stinger safely. You can take an antihistamine by mouth to reduce itching, swelling, and hives.
  • Try a pain reliever and use an ice pack to dull pain caused by the sting. In some cases, people get corticosteroids to lessen swelling and inflammation.
  • If you have symptoms of anaphylaxis, you need to use an epinephrine auto-injector (Auvi-Q or EpiPen) and call 911.

6. Latex allergy

You may have a mild reaction, like itchy red skin, from latex in gloves, condoms, or other things when you have a latex allergy. You could also have symptoms like:

  • Teary, irritated eyes
  • Runny nose
  • Sneezing
  • Cough
  • Wheezing

It’s less common, but some people can have anaphylaxis from latex.

To treat this allergy, you may need to take antihistamines. Your doctor may also recommend always keeping an epinephrine auto-injector (Auvi-Q or EpiPen) with you in case of emergency.

 To manage a latex allergy:

  • Avoid anything that has latex in it.
  • Wear a bracelet that lets people know you have a latex allergy.
  • If you have an anaphylactic reaction, immediately use an epinephrine auto-injector and call 911.

7. Food allergy

Some foods may bother you. But that doesn’t necessarily mean you have an allergy.

When you have an allergic reaction to food, it usually happens within minutes after you eat the food. These allergies can be mild or severe. For instance, some children must avoid peanuts in order to prevent a life-threatening anaphylactic reaction.

Milk, fish and shellfish, nuts, soybeans, wheat, and eggs are among the most common foods that cause allergies. Your doctor can help you pinpoint your triggers so you can avoid them.

Food allergy symptoms can include:

  • Wheezing or trouble breathing
  • Hives
  • Vomiting
  • Diarrhea
  • Swelling around your mouth

 To manage a food allergy:

  • Avoid the foods that your body doesn’t handle well.
  • If you think you have an allergy, ask your doctor to check it.
  • If you have a food allergy, you should carry an epinephrine auto-injector that you can use in an emergency. You should also call 911 immediately if you have symptoms of anaphylaxis.

8. Drug allergy

Some people are allergic to certain medicines, such as penicillin or aspirin.

Symptoms can range from a mild reaction like a skin rash a few days after you start a drug to an immediate, serious reaction. These can lead to anaphylaxis. Serious symptoms include:

  • Hives
  • Itchy eyes and skin
  • Flushing
  • Belly pain, nausea, and vomiting
  • Swelling in your mouth, throat, hands, and feet
  • Feeling lightheaded or passing out

For serious reactions, including anaphylaxis, you’ll need to call 911, and you may be need to be treated in the hospital. For milder symptoms, your doctor may give you an antihistamine or steroids.

Talk with your doctor if you know you have a drug allergy or think you might. They may refer you for allergy testing.

Even when you know what you're allergic to, you may not know how you're coming in contact with it. Hidden sources of allergy triggers are all around us.

Indoor pollution 

Studies have shown that indoor air pollution is often at least twice as high as what you get outdoors. If you're staying inside with the windows shut to avoid pollen, you may not be helping your situation. The Environmental Protection Agency recommends air purifiers and good HVAC filters to help improve your indoor air quality.

Vacuum cleaners

Allergens are tiny enough to go through a basic filter, rocketing out of the vacuum's exhaust. 

Much as we might all like to have a doctor-approved excuse for giving up on housework, that's not an option. People with allergies need to vacuum regularly since a buildup of dust -- full of allergens like pollens, dust mites, and pet hair -- is the last thing you need.

So instead, shell out for a vacuum with a HEPA (high-efficiency particulate air) filter, which will be fine enough to catch most allergy-irritating particles. Another option is a central vacuum -- if your house has one installed -- since at least then the allergens aren't being dispersed in your living space. 

Cleaning products 

Although cleaning products are not technically allergens, they can irritate the airways and trigger serious symptoms.

The key is to prevent the odor from the cleaning products from being heavy during cleaning. Make sure you have good ventilation by opening a window or running an exhaust fan.


It's not just the animal dander. Pets are prime culprits for bringing hidden allergy triggers into the house. When they go outside, they can pick up pollen and mold spores. Then they come in and sit on the couch, your bed, and you. The only solution is keeping your pets indoors or bathing them regularly.


Visitors can also bring hidden allergy triggers, like cat dander, on their clothes and bags and leave them behind on the way out. 

Treat your guests' belongings as warily as you would their cat. Ask guests to put their things in a closed room, then don't go in. Or you could even ask guests to leave their coats and bags in the garage. If none of that works, try to meet your friends outside your home.

Humidity -- too much or too little

Moisture helps mold grow. Dust mites also love a damp environment. So experts say you should keep humidity levels at 40% or below if you have allergies.

But air that's too dry -- under 20% humidity -- can affect you too. When the air is dry, your body tries to make up for it by making extra mucus in your nasal passages, which can leave you stuffed up.

Here's a tip: Get a hygrometer, a simple device that reads the humidity in your home. That way, depending on the moisture levels, you can either humidify or dehumidify.

Electrical appliances 

Certain household appliances and electronics, including laser printers, generate ozone. Ozone is a gas that's a well-known irritant for people with allergies. That's why people with asthma should stay inside on days with high ozone levels. But what's even worse is that many air cleaners deliberately churn out ozone to freshen the air.

Stoves and heaters 

Combustion in gas stoves, fireplaces, kerosene lamps, and many other devices and appliances can produce nitrogen dioxide and other pollutants. If they're not vented to the outside, the gases they release will move into your living space. 

If possible, avoid using unvented appliances. Also, use fireplaces, portable kerosene stoves, and wood stoves only occasionally.

Furniture, rugs, and home improvements

Many furnishings and construction materials contain formaldehyde and other volatile organic compounds (VOCs) that might irritate your airways. They include the glue used in carpet installation, the particleboard on your kitchen cabinets, the foam in your furniture, or the insulation in your walls.

Most irritants will fade over time but can take weeks or months. 

If possible, start with prevention. Choose products that are less likely to cause symptoms. And ventilate your home while they're being installed so the irritant doesn't become too concentrated.


Someone else's on-the-job exposure to irritants can affect you, too. If someone in your family works at a factory, garage, or laboratory -- or anywhere else with chemical irritants -- they can bring them home. And that could start you sneezing and coughing. Ask them to change their clothing after work or as soon as they get home.

Global warming

Many experts believe climate change could be making allergy symptoms worse. Global warming is tied to higher carbon dioxide levels. Some kinds of plants are loving it, and their pollen season is getting longer.

Aside from doing your bit to slow climate change, you can do little about this alone. Just be aware that the pollen season might be coming sooner than you expect, and be ready for it.

 If you think you have allergies, you and your doctor will need to do some detective work to figure out what is making you sneeze or itch. 

Track your allergy symptoms

Keep track of every symptom you have; they're all important clues to what you might be allergic to and how serious your allergy is. Signs of an allergic reaction include:

  • Chest tightness
  • Diarrhea
  • Feeling faint, confused, weak, or about to pass out
  • Hives -- small reddish bumps that look like bug bites suddenly appear on your skin
  • Itchy, dry rash
  • Odd taste in your mouth
  • Nausea or vomiting
  • Red skin, often around your eyes
  • Runny nose or sneezing
  • Stomach pain
  • Swollen lips, tongue, or throat
  • Trouble swallowing

Look for suspects

Allergens enter your body in different ways. You’ll be that much closer to finding your culprit if you can figure out how.

  • By injection. This could be medicines given by needle or venom from insect bites or stings.

  • Mouth. Common food allergens include peanuts, fish, and shellfish.

  • Nose and lungs. They can be particles that float in the air, like pollen, animal dander, dust, or mold.  

  • Through your skin. These can include poison ivy, oak, or sumac. Chemicals in cosmetics, dyes, and latex can also spark a reaction.

Keep a diary

Tracking when you have symptoms and what was going on when you had them in a diary helps pinpoint the cause. It also can help you figure out what makes them worse. 

Think about anything that's changed in your routine, like eating something different or going to new places. Be sure to note if other family members have allergies and what they are.

This info will also help your doctor decide what you're allergic to and how to treat it. 

If you still can’t figure out your allergies, you can get help from the experts. The Asthma and Allergy Foundation of America’s free info line, 800-727-8462, is open weekdays from 10 a.m. to 3 p.m. ET. This line isn’t for emergencies. Call 911 if you’re having a serious reaction.

An allergist can help you figure out what and how serious your allergies are. They might:

  • Discuss your symptoms 
  • Ask about your medical history
  • Do a physical exam, looking at your eyes, nose, ears, chest, throat, and skin during the exam 
  • Use blood, patch, or skin tests to verify your allergy
  • Prescribe over-the-counter or prescription meds or allergy shots to relieve your symptoms
  • Tell you how to change your environment or personal habits so you’ll feel better