What do I need to know about allergies?

There’s nothing inherently dangerous about pollen or milk. But some people’s bodies mistake these substances as a threat. Their immune system goes on the attack to try to get rid of those harmless invaders (allergens). Allergy symptoms are the result.

Allergens can include:

• Things you swallow, such as food or medicine
• Particles you breathe in, such as pollen, dust, mold and pet dander (flakes of skin)
• Substances you brush up against, such as poison ivy

When you’re exposed to an allergen, your body sets off a chain of events, says Irene Paek, MD. She’s an allergist and immunologist at ProHEALTH Care Associates, part of Optum, in Bethpage, New York.

Step 1: Your body overreacts and releases a chemical called histamine.¹

Step 2: Histamine kicks off different processes within your body to deal with the threat.¹ It can fire up your nerves and create itching. It might also lead to a runny nose.

Step 3: You react to the histamine. If you feel itchy, you may physically brush the allergen off your skin. Maybe your runny nose causes you to grab a tissue. Blowing your nose helps flush allergens from your system.

You can think of the allergic response as one big exaggeration. The body is trying its hardest to protect itself from something that isn’t a danger.

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There is a wide range of substances that might cause allergy symptoms. They typically fall into one of several categories.

Seasonal and outdoor allergens. These happen when plants begin sprouting and pollinating. Different plants can cause allergy symptoms, depending on the season. Common examples include pollen from:²

• Trees
• Flowers
• Grass
• Ragweed

Foods. Even a small amount of a food allergen can cause a severe reaction. “A peanut allergy is the most pervasive food allergy,” says Robert Corriel, MD. He’s an allergist at ProHEALTH Lake Success Allergy, part of Optum, in New Hyde Park, New York. “It sticks around longest.” The most common food allergens are:²

• Peanuts
• Soy
• Wheat
• Eggs
• Shellfish
• Milk
• Tree nuts, such as walnuts and pecans

Stinging insects. Getting stung by a bee doesn’t feel good for anyone. But stings can be dangerous for people who are allergic to the insect’s venom. Examples of stinging insects include:³

• Certain types of bees
• Hornets
• Yellow jackets
• Fire ants

Indoor allergens. If you have allergy symptoms indoors, especially in a home, they may be caused by substances such as:⁴

• Dust
• Mold
• Cockroach droppings
• Pet dander

Medications.⁵ All medications have the potential to cause side effects. But for some people, medications may cause an allergic reaction. Some people are even allergic to certain dyes in medications. “You can have allergic reactions to just about any medication on the planet,” Dr. Corriel says.

If you think you’re having an allergic reaction to your medicine, contact your doctor right away. If you’re having severe symptoms, such as trouble breathing, call 911.

Things you touch. When allergens affect your skin, you may have rashes, hives and/or itching. Plants are common culprits, such as poison ivy. Other common allergens in this category include:

• Latex
• Fragrances
• Cosmetic ingredients
• Soaps
• Detergents

Have allergies that are mostly skin-related? Your doctor may suggest certain creams and ointments to ease itchiness and redness. In more severe cases, they may give you medication.

There does appear to be a family link when it comes to allergies. Parents with allergies are more likely to have children with allergies, Dr. Paek says.

That’s why an allergist will ask about your family history as part of your first exam. If multiple people in your family have allergies, you might get them, too. (Read more about allergies in kids.)

Allergies can start at any age. You may start to have allergies when you’re older, even if you’ve never had a problem in the past, says Dr. Corriel. You may have eaten shrimp your whole life, but it could start causing intense reactions seemingly out of the blue.

Seasonal allergies may be especially problematic, Dr. Corriel adds. Pollen seasons are getting longer and stronger due to climate change. As a result, symptoms may worsen.

The good news? You’re not always stuck with allergies once you have them.

“For the most part, allergies tend to wax and wane through life,” he says. “You can outgrow an allergy from childhood. Or you might need treatment as a child and then not as a young adult, even if you still have the allergy.”

The most common allergy test is done on a small patch of skin, usually on your arm, Dr. Paek says. A doctor will put a small amount of an allergen on your skin. About 15 minutes later, they will check your skin. (Looking for a doctor near you? Search Optum providers now.)

“If you have an allergy to something, you’ll have an allergic response,” Dr. Paek says. “You’ll have a small, itchy bump where the test was placed.”

Blood work can also find specific allergies.² When your body finds an allergen, it makes a chemical called an antibody. Each antibody is specific to a single allergen. For example, you can be allergic to several kinds of pollen. Your body will create an antibody for each one. A blood test can find these antibodies and their levels in your blood.

Symptoms of seasonal and indoor allergies can range from slight to severe. The most common symptoms are:

• Congested or runny nose
• Red, itchy, watery eyes
• Sneezing
• Ear congestion
• Postnasal drip, which can cause a dry cough and irritated throat
• Itchiness and irritation in the sinuses and throat
• Headache
• Coughing
• Feeling tired
• Skin rash or hives

Antihistamine medication is the main remedy for these symptoms. You can buy these medications over the counter at your local pharmacy or get a prescription from your doctor. Common medications include:

• Loratadine (Claritin®, Alavert®)
• Diphenhydramine (Benadryl ®)
• Cetirizine (Zyrtec®)
• Fexofenadine (Allegra®)
• Levocetirizine (Xyzal®)

How do you combat dust, mold or insect droppings that cause your allergies? You may need a thorough cleaning of your home to help stop symptoms. (Stuffy nose? How to tell if it’s a cold, allergies or COVID.)

Luckily, there are ways to stop allergy symptoms before they begin. Some of these tips might keep your symptoms from happening entirely.

• Use a nasal spray or bulb syringe with saline. It can flush allergens from your sinuses, which can ease itching and swelling.
   
• Try eye drops. They can lubricate your eyes and rinse out allergens.
   
• Wash your sheets at least once a week in hot water. Keeping your linens clean can wash away allergens that might irritate your skin or eyes while you sleep.
   
• Keep the clothing you wear outside far away from your bedroom. Getting undressed in the hallway or laundry room can keep allergens out of your bedroom.
   
• Shower after you have been outside. A shower can rinse pollen off your skin and hair. Shower steam can flush allergens from your sinuses.
   
• Pay attention to pollen counts. Plan outdoor activities based on when pollen counts are lowest. Pollen levels tend to peak in the morning. They can be higher on dry, windy days or on hot days.
   
• Invest in an air purifier. High-efficiency particulate air (HEPA) filters are especially good at removing allergens from the air. They can remove more than 99% of allergens in the air, including dust and pollen. Think about putting a HEPA filter in one room and keeping that room closed. That way, your home can have at least one “clean room” where you can spend time when allergy symptoms are acting up.
   
• Start your medication before allergy season starts. If you know that every fall you’ll be going to battle against ragweed, ask your doctor about starting your medication a couple of weeks before the pollen starts to fly. That way, you can get ahead of your symptoms, and any that you do have may be less severe. 

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Food allergies can cause symptoms far beyond your stomach. Your skin, heart, lungs and airways can also be affected by eating an allergen.

Food allergy symptoms typically begin within two hours of eating. But most start within minutes. Symptoms can include:

• Vomiting
• Stomach cramps
• Hives
• Shortness of breath
• Trouble swallowing
• Swelling of the tongue, affecting the ability to breathe or talk
• Coughing
• Dizziness

Very rarely, you may have such a strong reaction to a food allergen that it results in a sudden drop in blood pressure. That’s called anaphylactic shock. It’s a life-threatening reaction.⁸ It’s most common with food and drug allergies, as well as insect stings.¹⁰ Anaphylactic shock is marked by:

• Shortness of breath
• Throat swelling
• Dizziness
• Severe headache
• Vomiting
• Fainting

If you go into anaphylactic shock, you’ll likely need a shot of epinephrine. The medicine relaxes your throat muscles, making it easier to breathe.⁶

Some people with food allergies carry an epinephrine injector (EpiPen®) for emergencies. People allergic to stinging insects might also carry one.

Avoidance is the main way to stop food allergy symptoms, Dr. Corriel says. Your allergist may be able to help you create a plan to slowly expose you to that food over time. But the easiest and safest method is finding something else to eat, he says.

There is no cure for allergies. But if your symptoms affect your quality of life, your doctor may suggest allergy shots. They’re also known as immunotherapy. This treatment is a more involved, lengthy way to manage symptoms.

Immunotherapy exposes you slowly to an increasing amount of a specific allergen through injections. It’s meant to “train” your body to tolerate allergens instead of reacting with severe symptoms. Your first injections take place over a period of months. Then, they’re followed by maintenance shots for several years.

Immunotherapy is typically recommended only if:

• You’re sensitive to several allergens, or
• You have severe or worsening symptoms

With the right plan, you can learn to manage your allergy symptoms, so that they don’t manage you.

1. American Academy of Allergy Asthma & Immunology. Histamine defined. Accessed July 26, 2022.
2. American Academy of Allergy Asthma & Immunology. Allergic reactions. Last reviewed September 28, 2020. Accessed July 26, 2022.
3. American Academy of Allergy Asthma & Immunology. Stinging insect allergy. Last reviewed September 28, 2020. Accessed July 2, 2022.
4. American Academy of Allergy Asthma & Immunology. Indoor allergens. Last reviewed September 28, 2020. Accessed July 2, 2022.
5. American Academy of Allergy Asthma & Immunology. Medications and drug allergic reactions. Last reviewed September 28, 2020. Accessed July 2, 2022.
6. American College of Allergy, Asthma & Immunology. Food allergy. Accessed July 2, 2022.
7. National Center for Complementary and Integrative Health. Seasonal allergies at a glance. Last updated March 2019. Accessed July 26, 2022.
8. American College of Allergy, Asthma & Immunology. Anaphylaxis. Last reviewed January 29, 2018. Accessed July 26, 2022.
9. American College of Allergy, Asthma & Immunology. Allergy immunotherapy. Accessed July 26, 2022.
10. MedlinePlus. Anaphylaxis. Last reviewed January 23, 2022. Accessed August 8, 2022.

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