Allergies

What are allergies?

Allergies are a reaction by the body's immune system to harmless substances that it sees as harmful. The allergy-causing substances are called allergens.

How do they occur?

Your immune system is your body's natural defense against infection and other foreign material. Before you can have a reaction to a particular substance, your immune system must first be sensitized to it. This happens in an earlier contact with the substance. Once sensitized, your body will react every time you have contact with that substance. Many substances can cause an allergic reaction.

The most common are:

pollen
mold
dust mites
animal dander
latex
medicines
insect stings
foods

The allergens may cause different kinds of allergic reactions. The most common allergic conditions are hay fever, asthma, and skin allergies.

Pollen of trees, grasses, weeds, or molds cause hay fever.
Pollens, molds, and house dust can trigger asthma attacks.
Contact with plants, nickel in jewelry, dyes, and skin or hair care products may cause an allergic skin reaction.

A special type of skin allergy is eczema. The cause of eczema is usually not known.

Some people develop allergies to medicines or foods. Common foods that may cause allergy symptoms are fish, eggs, milk, nuts, peanuts, and wheat. Food allergies often occur in children, who may outgrow them.

It is also possible to have an allergic reaction to sunlight, temperature extremes, or other things in your physical environment. It is not known why some people develop allergies to certain substances. Allergies run in families, but not every family member may be allergic to the same thing. Sometimes an allergic reaction may be severe. This is called anaphylaxis. It is a life-threatening emergency that can affect breathing and circulation within several minutes. Insect stings, certain foods, and drugs such as penicillin are some of the more common causes of severe allergic reactions.

What are the symptoms?

The symptoms of an allergic reaction depend on the type and severity of the reaction. Common symptoms of an allergy are:

sneezing
watery eyes
stuffy or runny nose
itching
swelling
a rash or hives (raised, red, itchy areas on the skin)
stomach cramps
diarrhea

Some of the symptoms of a severe allergic reaction are:

fast pulse
trouble breathing, including wheezing
nausea and vomiting
swelling of the lips, tongue, or throat
hives
pale, cool, damp skin
drowsiness, confusion, or loss of consciousness

How are they diagnosed?

Your health care provider will ask about your history of symptoms and examine you. You may have tests to find out which allergens are causing your symptoms. For most people the best tests are skin scratch or prick tests. For these tests your provider looks for reactions to tiny amounts of suspected allergens placed under your skin. In some cases you may have blood tests to look for antibodies to possible allergens. To identify a food allergy, your provider may suggest that you try to find which foods cause a reaction by not eating certain foods for a while. Then you can carefully try eating these foods again, one by one, to see if your symptoms come back.

How can I avoid problems?

It is not easy to avoid most allergens. To avoid suffering with a runny nose and sneezing, try to figure out what allergens cause problems for you. Then stay away from them as much as possible. Here are some tips on how to avoid common allergens:

Pollen from trees, grass and weeds. Shower or bathe before bedtime to wash off pollen in your hair and on your skin. Avoid going outside during the time of year when your allergies cause the most problems, especially on dry, windy days. Keep windows and doors shut at home and in your car, and use an air conditioner. Special air filters, such as HEPA and electrostatic filters, can help reduce allergens in the air.
Mold. Remove houseplants. Frequently clean shower curtains, bathroom windows, damp walls and indoor trashcans. In areas where mold has built up, use a mixture of water and chlorine bleach to kill it. Don't carpet bathrooms or other damp rooms. Use mold-proof paint instead of wallpaper. Reduce the humidity in your home to 50% or less.
Pet dander. If your allergies to dander (skin and hair from animals) are severe, you may need to give your pets away, or at least keep them outside.

How are they treated?

If avoiding allergens doesn’t help enough, you may need to try allergy medicines. Some common types are described below:

Antihistamines help reduce sneezing, runny nose and itchiness. Antihistamines that you can buy without a prescription relieve symptoms just as well as prescription medicines do. However, they tend to cause tiredness and dry mouth. Prescription antihistamines are less likely to cause tiredness or dry mouth. Before you take an allergy or cold medicine, check the label for a drug called phenylpropanolamine, or PPA. The U.S. Food and Drug Administration has recalled this drug for safety reasons. If a medicine contains PPA, don't take it.
Pseudoephedrine is a decongestant that helps temporarily relieve a stuffy nose. Pseudoephedrine, currently one of the only decongestants on the market in the U.S., comes as pills, nose sprays and nose drops. It is worth noting that here in Oregon, you need a prescription for this medicine- due to its ability to be synthesized into methamphetamines. Decongestant tablets or liquids are best used only for a short time (1 to 2 weeks). Nose sprays and drops shouldn’t be used for more than 3 days because your body can become dependent on them. This causes your nose to feel even more stopped-up when you stop using them. Decongestants can raise blood pressure in some people, so it’s a good idea to talk to your family doctor before using them.
Cromolyn sodium is a nasal spray that helps prevent your body from reacting to inhaled allergens. Cromolyn sodium is more helpful if you use it before you’re exposed to allergens. This medicine may take up to 2 to 4 weeks to start working. It is available without a prescription.
Nasal steroid sprays reduce the inflammatory reaction of your nasal tissues to inhaled allergens. Your doctor may prescribe a steroid spray to relieve the swelling in your nose so that you feel less stopped-up. This medicine may take a couple of weeks to start working.
Eye drops. Eye drops can help itchy, watery eyes. You can buy these drops without a prescription.

Your doctor might suggest eye drops that contain an antihistamine-decongestant combination. These drops are available in over-the-counter and prescription forms. Be sure to read the directions before using any medication. Many of these eye drops should not be used for longer than a few days.

In some cases, your provider may suggest allergy shots. A mixture is prepared that contains the allergens identified in your allergy tests. The mixture is injected into your skin in tiny but increasing amounts over the course of many months. Over time, the shots make you less sensitive to the allergens. Usually after 4 to 6 months of allergy shots you will begin to have relief from your allergies. However, you will probably need to continue the shots for 2 to 3 years or longer.

If you have a severe allergic reaction, call 911 right away. Use an EpiPen or Ana-Kit if you have one. Once you know that you have a severe allergy, always carry an Epi-pen or Ana-Kit. Teach family members and coworkers how to help you if you have a severe reaction.

How long will the effects last?

The effects of an allergic reaction depend on how much you have been exposed to an allergen and how severe your allergy is. You may have symptoms for several minutes, hours, or days. Some people outgrow their allergies. Others may have allergies all their life.

How can I take care of myself?

Follow your health care provider's instructions.
Try to avoid the things you are allergic to.
If you tend to have severe allergy reactions, ask your provider about carrying medicine with you, such as an EpiPen or Ana-Kit, for emergency use. Wear an ID, such as a Medic Alert bracelet, that lists your severe allergies.

How can I help prevent allergies?

There is no known way to prevent allergies. However, some research has shown that breast-fed babies may be less likely to develop allergies and asthma. Also, if your family has a very strong history of allergies, you might try to avoid your family's most common allergens. For example, you may need to stay away from cats. This might help stop you from developing severe symptoms.

Where can I get more information?

Many organizations provide support and information for people with allergies and asthma. Here a few:

The American Academy of Allergy, Asthma & Immunology offers a variety of services. They can provide educational materials, pollen count reports and maps, and a physician referral directory. Call 800-822-2762 or visit their Web site at http://www.aaaai.org.
The Asthma and Allergy Foundation of America offers educational programs and services. They also offer asthma and allergy support groups across the country for adults, parents, teens, and caregivers. Call 800-727-8462 or visit their Web site at http://www.aafa.org.
The American Lung Association offers educational materials and support group information. Check your local telephone listings for a chapter near you, call 800-586-4872, or visit their Web site at http://www.lungusa.org.
The Food Allergy & Anaphylaxis Network is a worldwide network that provides educational materials, allergy alerts, and research studies related to food allergies. Call 800-929-4040 or visit their Web site at http://www.foodallergy.org.

For more information about local support groups in your community, contact your healthcare provider or local hospital.