Allergies Learn about allergies

 

If you are like a lot of people, you are allergic to something. For most people, allergies mean itchy eyes and a drippy nose. But for a few people, allergies to things like bee stings or nuts cause a whole-body reaction that can be life-threatening. Whether your allergies are dangerous or just annoying, the information in our Learning Center can help you cope.
Get started learning more about allergies in topics such as:
Allergic Rhinitis.

What is allergic rhinitis?

Allergic rhinitis, often called allergies or hay fever, occurs when your immune system overreacts to particles in the air that you breathe—you are allergic to them. Your immune system attacks the particles in your body, causing symptoms such as sneezing and a runny nose. The particles are called allergens, which simply means they can cause an allergic reaction.
People with allergies usually have symptoms for many years. You may have symptoms often during the year, or just at certain times. You also may get other problems such as sinusitis and ear infections as a result of your allergies.
Over time, allergens may begin to affect you less, and your symptoms may not be as severe as they had been.

What are the symptoms of allergic rhinitis?

In most cases, when you have allergic rhinitis:

• You sneeze again and again, especially after you wake up in the morning.
• You have a runny nose and postnasal drip. The drainage from a runny nose caused by allergies is usually clear and thin. But it may become thicker and cloudy or yellowish if you get a nasal or sinus infection.
• Your eyes are watery and itchy.
• Your ears, nose, and throat are itchy.

Which allergens commonly cause allergic rhinitis?

You probably know that pollens from trees, grasses, and weeds cause allergic rhinitis. Many people have allergies to dust mites, animal dander, cockroaches, and mold as well. Things in the workplace, such as cereal grain, wood dust, chemicals, or lab animals, can also cause allergic rhinitis.
If you are allergic to pollens, you may have symptoms only at certain times of the year. If you are allergic to dust mites and indoor allergens, you may have symptoms all the time.

How is allergic rhinitis diagnosed?

To find out if you have allergies, your doctor will ask about your symptoms and examine you. Knowing what symptoms you have, when you get them, and what makes them worse or better can help your doctor know whether you have allergies or another problem.
If you have severe symptoms, you may need to have allergy tests to find out what you are allergic to.

• Your doctor may do a skin test. In this test your doctor puts a small amount of an allergen into your skin to see if it causes an allergic reaction.
• Your doctor may order lab tests. These tests look for substances that put you at risk for allergies.

How is it treated?

There is no cure for allergic rhinitis. One of the best things you can do is to avoid the things that cause your allergies. You may need to clean your house often to get rid of dust, animal dander, or molds. Or you may need to stay indoors when pollen counts are high.
Unless you have another health problem, such as asthma, you may take over-the-counter medicines to treat your symptoms at home. If you do have another problem, talk to your doctor first. Others who also should talk to their doctor before starting self-treatment include older adults, children, and women who are pregnant or breast-feeding.
If your allergies bother you a lot and you cannot avoid the things you are allergic to, you and your doctor can decide if you should get allergy shots (immunotherapy) to help control your symptoms. For allergy shots to work, you need to know what you are allergic to.
Finding the treatment that works best for you may take a little time.

Food Allergies

What is a food allergy?

When you have a food allergy, your body thinks certain foods are trying to harm you. Your body fights back by setting off an allergic reaction. In most cases, the symptoms are mild—a rash, a stuffy nose, or an upset stomach. A mild reaction is no fun, but it isn't dangerous. A serious reaction can be deadly. But quick treatment can stop a dangerous reaction.
Allergies tend to run in families. You are more likely to have a food allergy if other people in your family have allergies like hay fever, asthma, or eczema (atopic dermatitis).
Food allergies are more common in children than adults. Children sometimes outgrow their food allergies, especially allergies to milk, eggs, or soy. But if you develop a food allergy as an adult, you will most likely have it for life.

Food allergy versus food intolerance

Food intolerances are much more common than food allergies. True food allergies are a reaction to food or food additives by your body's immune system.
Many people think they have a food allergy, but in fact they have a food intolerance. Food intolerance is much more common. It can cause some of the same symptoms as a mild food allergy, like an upset stomach. But a food intolerance does not cause an allergic reaction. A food intolerance can make you feel bad, but it is not dangerous. A serious food allergy can be dangerous.

What are the symptoms?

Food allergies can cause many different symptoms. They can range from mild to serious. If you eat a food you are allergic to:

• Your mouth may tingle, and your lips may swell as you start to eat the food.
• You may have a stuffy nose, wheeze, or be short of breath when the allergens reach your mouth and lungs.
• You may have cramps, an upset stomach, or diarrhea as the food is digested.
• You may feel dizzy or lightheaded if your blood pressure drops as the allergens circulate through your bloodstream.
• You may have itchy skin with red, raised bumps called hives as the allergens reach your skin.

Kids usually have the same symptoms as adults. But sometimes a small child just cries a lot, vomits, has diarrhea, or does not grow as expected. If your child has these symptoms, see your doctor.
Some people have symptoms after eating even a tiny bit of a problem food. As a rule, the sooner the reaction begins, the worse it will be.
The most severe reaction is called anaphylaxis (say "ANN-uh-fuh-LAK-suss"). It affects your whole body. Anaphylaxis can start within a few minutes to a few hours after you eat the food. And the symptoms can go away and come back hours later. If you have anaphylaxis:

• Your throat and tongue may swell quickly.
• You may suddenly start wheezing or have trouble breathing.
• You may feel sick to your stomach or vomit.
• You may feel faint or pass out.

Anaphylaxis can be deadly. If you have (or see someone having) any of these symptoms, call 911 right away.

What foods most often cause a food allergy?

A few foods cause most allergies. A food that causes an allergy is called a food allergen. The protein in the food causes the problem.

• Milk, eggs, peanuts, tree nuts, fish, shellfish, wheat, and soy cause most problems in children.
• Milk, peanuts, tree nuts, fish, and shellfish cause most problems in adults.

If you are allergic to one food, you may also be allergic to other foods like it. So if you are allergic to shrimp, you may also be allergic to lobster or crab.

How is a food allergy diagnosed?

Your doctor will ask questions about your medical history and any family food allergies. And he or she will do a physical exam. Your doctor will also ask what symptoms you have. He or she may want you to write down everything you eat and any reactions you have. Your doctor will consider other possibilities that could be confused with food allergies, such as a food intolerance.
Because food allergies can be confused with other problems, it is important for your doctor to do a test to confirm that you have a food allergy. Your doctor may first start out with either skin testing or a blood test to determine what you are allergic to, but an oral food challenge is the best way to diagnose a food allergy. In an oral food challenge, you will eat a variety of foods that may or may not cause an allergic reaction. Your doctor watches to see if and when a reaction occurs.
A skin prick test can help to find out which foods will cause a reaction. The doctor will put a little bit of liquid on your skin and then prick your skin. The liquid has some of the possible food allergen in it. If your skin swells up like a mosquito bite, your doctor knows that you are allergic to that food. Your doctor may also do blood tests to look for the chemicals in your blood that cause an allergic reaction.

How is it treated?

The best treatment is to never eat the foods you are allergic to. Learn to read food labels and spot other names for problem foods. For example, milk may be listed as "caseinate," wheat as "gluten," and peanuts as "hydrolyzed vegetable protein." When you eat out or at other people's houses, ask about the foods you are served.
If you have a history of severe food allergies, your doctor will prescribe an allergy kit that contains epinephrine (say "eh-puh-NEH-fren") and antihistamines. An epinephrine shot can slow down or stop an allergic reaction. Your doctor can teach you how to give yourself the shot.
You can have symptoms again even after you give yourself a shot. So go to the emergency room every time you have a severe reaction. You will need to be watched for several hours after the reaction.
If you have had a serious reaction in the past, your chance of having another one is high. Be prepared.

• Keep an allergy kit with you at all times.
• Wear a medical alert bracelet to let others know about your food allergy.
• Check the expiration dates on the medicines in your kit, and replace the medicines as needed.

If your child has a food allergy, what else should you think about?

Talk to your child's teachers and caregivers. They should know how to keep problem foods away from your child. Teach them what to do if your child eats one of these foods by mistake.
If your child has ever had a severe reaction, keep an allergy kit nearby at all times. Some kids carry their kit in a fanny pack. Have your child wear a medical alert bracelet. Teach all caregivers to act quickly. They should:

• Know the signs of a severe reaction.
• Know how to give an epinephrine shot.
• Call 911 right away.