KayaWell Icon

What Is an Allergy?

This article explains the basics of an allergic reaction. Learn what happens when your immune system goes on high alert.

Who Gets Allergies?

Anyone can get them, at any age. You could develop them as a child, or you might not have any symptoms until you’re an adult.

What Causes an Allergic Reaction?

While your problem may seem to start in the nose or the eyes, allergies actually come from an immune system run wild.

While your problem may seem to start in the nose or the eyes, allergies actually come from an immune system run wild.

Spring Allergies
There's no cure but you can take steps to curb springtime allergies, from medication to household habits.

Summer Allergies
Summer allergies are usually triggered by pollen from grasses and weeds.

Fall Allergies
Ragweed, mold and dust mites are the biggest allergy triggers in the fall.

Winter Allergies
If you have indoor allergies such as mold and dust mites, you may notice symptoms more during winter, when you spend more time inside.

Hay Fever
Hay fever, also known as allergic rhinitis, is an immune disorder characterized by an allergic response to pollen grains and other substances. There are two types: seasonal, which occurs only during the time of year in which certain plants pollinate, and perennial, which occurs year-round.

Pollen Allergies
More than 25 million Americans are allergic to pollen from trees, grass, or weeds.

Mold Allergy
All of us are exposed to some mold every day, and usually, there are no problems. But if you have allergies to it, you can have a reaction if you’re around too much of it.

Dust Allergy
For creatures you can't even see, dust mites can stir up a lot of trouble.

Dog Allergy
For a person with dog allergies, life in a dog-loving country isn't easy. Approximately 37%-47% of American households have a dog.

Cat Allergy
About 10% of the U.S. population has pet allergies and cats are among the most common culprits. Cat allergies are twice as common as dog allergies.
You can treat allergy symptoms with over-the-counter and prescription medications, as well as allergy shots.  Lifestyle changes like using air filters and avoiding triggers are important, too. 

Types of Allergy Medications
Learn all about the different over-the-counter and prescription medicines that can help ease annoying symptoms.

What Are Antihistamines?
When medicine is needed to stem allergy symptoms, antihistamines are often first in line. Find out how they can help and learn about possible side effects.

How Decongestants Work
When allergies make your nose stuffed up, an antihistamine generally won't help. But a decongestant might.

Anticholinergic Nasal Allergy Sprays
Atrovent nasal spray can help with the runny nose that may come with allergies. Find out if it’s right for you.

Steroid Nasal Sprays
Nasal steroid sprays are available over the counter or by prescription.  They are often the first treatment recommended for nasal allergies.

Allergy Eye Drops
Allergy eyedrops are liquid medicines used to treat symptoms of eye allergies.

Leukotriene Inhibitors
Montelukast (Singulair) is a prescription drug that reduces congestion in your nose, cuts down on sneezing, itching, and eye allergies, and reduces inflammation in your airways.

Mast Cell Inhibitors
Cromolyn sodium (Nasalcrom, Crolom), a mast cell inhibitor, is used to prevent allergic symptoms like runny nose and itchy eyes. 

Allergy Shots
Allergy shots help your body get used to things that trigger an allergic reaction. They aren't a cure, but in time your symptoms may improve and become less frequent.

When to Use Your Auto-Injector
An auto-injector -- such as EpiPen, Twinject, or Auvi-Q -- can treat extreme allergic reactions with an early, life-saving dose of epinephrine.

To pinpoint the allergy problem -- and determine the treatment – your doctor will ask questions about your symptoms and habits. You’ll also need various tests.

Finding the Cause of Allergies
An allergist may be able to help identify your allergy triggers. Several different types of allergy tests are used to do this.

Questions Your Doctor Will Ask You
Your doctor will likely ask you a series of questions to help determine if your problem is allergy related. Here’s what to expect.

Allergy Skin Test
Skin testing is one way your doctor can check on what causes your allergy symptoms.

Blood Test for Allergies
Allergy blood tests detect and measure the amount of allergen-specific antibodies in your blood. When you come into contact with an allergy trigger, your body makes antibodies against it,

Food Allergy Testing
Testing is the most controversial aspect of food allergy treatment. But new guidelines help doctors use food allergy tests in the best possible way.   

Allergy Symptom Diary
If you have a food allergy, you may need to keep a food diary – and remove certain foods from your diet – to determine exactly what you’re allergic to.

Elimination Diet
The elimination diet involves removing specific foods or ingredients from your diet that you and your doctor suspect may be causing your allergy symptoms (common allergy-causing foods include milk, eggs, nuts, wheat, and soy). Your doctor will supervise this diet over a few weeks.

Allergies and Asthma

Asthma attacks (worsening of asthma symptoms) can be triggered by allergies, which can temporarily increase the inflammation of the airways in a susceptible person.

Allergies and Sinusitis

Sinusitis is an inflammation or swelling of the tissue lining the sinuses. Allergies can trigger sinusitis.

What Happens in Anaphylaxis?

Sometimes, allergies can cause a life-threatening reaction called anaphylaxis. It's not common, but you should be aware of what to do if it happens.

Nasal Polyps

Nasal polyps are noncancerous, teardrop-shaped growths that form in the nose or sinuses. They’re often linked to allergies or asthma.