Know Your Allergy Triggers

Medically Reviewed by Sanjay Ponkshe on July 13, 2023
6 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.

You may think you know what the problem is -- your friend’s cat, certain plants, those dust “bunnies” under your bed. That's a start, and by all means, avoid something that bothers you.

But it also helps to keep notes on your symptoms -- when they start, how long they last, and whatever seems to bring them on. If it's hard to tell what's causing them, or if they become too hard for you to handle on your own, see a doctor about getting allergy tests. The tests will help pinpoint exactly what your triggers are.

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


In the spring and summer, the air is filled with pollen from fresh, growing things like grass, trees, and weeds. In some people, ragweed in the fall may trigger allergies.

Signs to watch for include:

  • Fatigue. This can be from poor sleep because your nose is stopped up.
  • Itchy eyes, nose, or roof of mouth
  • Runny, stuffy nose
  • Sneezing
  • Watery eyes, redness, or swelling

Do this:

  • Ask your doctor about taking meds like decongestants or antihistamines to ease your symptoms.
  • Keep your car and home windows closed during “high pollen” times.
  • Wear a baseball cap outside and wash your hands and face when you get inside.

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

Treatment may include medications such as steroid nasal sprays, antihistamines, or decongestants.

Do this:

  • 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, such as stuffed animals, curtains, and carpet.

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

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

Treatment is similar to that for dust mite and pollen allergies.

Do this:

  • Avoid mold and get rid of things that encourage its growth.
  • Repair any water damage or leaks in your home.
  • You may not want to keep plants inside because their soil can hold mold.
  • Use a dehumidifier to keep your home dry.
  • If you rake leaves in the fall, wear a mask.

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

It may take two or more years for you 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.

Symptoms include sneezing, congestion, and itchy and watery eyes.

Do this:

  • 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 would help, 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 such as antihistamines, decongestants, and nasal steroids to help. Allergy shots (immunotherapy) might also help.
  • If you have cockroach allergies, be sure to keep trash in closed containers and take it out of your home promptly. You may also want to consider getting an exterminator.

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

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

If you get stung by an insect, you can expect pain, swelling, and redness and heat around the sting site. Those 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 the face, eyelids, ears, mouth, hands, or feet
  • Belly cramps, nausea, vomiting, or diarrhea
  • Feeling dizzy or passing out

Do this:

  • Make yourself unattractive to insects. Don’t wear brightly colored clothes and avoid scented lotions or cosmetics.
  • Keep insecticide handy, wear shoes outdoors, and stay away from 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 curb swelling and inflammation.
  • If you have symptoms of anaphylaxis, you need to use an epinephrine auto injector (Auvi-Q or EpiPen) and call 911.

You may have a mild reaction, like itchy red skin, from latex in gloves, condoms, or other things. If it’s a true 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 you keep an epinephrine auto injector (Auvi-Q or EpiPen) with you at all times in case of emergency.

Do this:

  • 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.

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 problem 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 exactly what your triggers are so you can avoid them.

Symptoms can include:

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

Do this:

  • 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 case of emergency. You should also call 911 immediately if you have symptoms of anaphylaxis.

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 a severe and immediate reaction. They can be concerning because they can lead to anaphylaxis. Serious symptoms include:

  • Hives
  • Itchy eyes & skin
  • Flushing
  • Belly pain, nausea, vomiting
  • Swelling in the mouth, throat, hands, and feet
  • Feeling light headed or passing out

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

Do this:

  • For serious reactions, including anaphylaxis, you’ll need to call 911 and you may be hospitalized. For milder symptoms, your doctor may give you an antihistamine or steroids.
  • If you know you have a drug allergy or think you might, talk with your doctor. The doctor may refer you for allergy testing.

Show Sources


Asthma and Allergy Foundation of America.

National Institutes of Health.

American Academy of Allergy Asthma and Immunology: “Types of Allergies: Allergic Rhinitis,” “Types of Allergies: Drug Allergies,” "Types of Allergies: Hives (Urticaria),” “Types of Allergies: Insect Sting Allergy,” “Types of Allergies: Latex Allergy.”

American Family Physician: “Things That Can Cause Asthma and Allergies.”

Mayo Clinic: “Allergies: Symptoms and Causes,” “Drug allergy: Symptoms,” “Symptoms: Wheezing.”

Food Allergy Research and Education: “About Anaphylaxis,” “Shellfish,” “Symptoms,” “Treatment & Managing Reactions.”

CDC: “Food Allergies in Schools.”

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