Nothing to sneeze at

Chances are, you have an allergy or know someone who does. According to the American Academy of Allergy, Asthma and Immunology, allergies affect about 50 million Americans, and this number is on the rise. (For example, the prevalence of peanut allergy in American children has doubled in the last 5 years.) Ironically, experts believe that the increase in allergies is a result of the Western world's super-clean way of life - the destruction of many infectious diseases may have altered our immune systems so that they overreact when exposed to things that should not be a problem.

There are many kinds of allergies, including hay fever, asthma and reactions to food, insect stings, and latex. Symptoms vary, with the most serious, anaphylaxis, potentially leading to death.

An allergen is any substance that can trigger an allergic response from the body's immune system. Many people react to pollen, animal dander, mold, and droppings from cockroaches and dust mites. It's not known why these and other substances cause allergic reactions in some people, but allergies do tend to run in families. If one parent has allergies, the likelihood that a child will have allergies is nearly 50%, or 70% if both parents have allergies.

Researchers do know that antibodies play a role. Antibodies are proteins in the bloodstream that are created by our bodies to target and destroy foreign substances. Each type of antibody targets only one foreign substance. When allergens enter the body for the first time, the immune system produces allergen-specific Immunoglobulin E, or IgE, antibodies. They attach themselves to mast cells, found in large quantities in the eyes, nose, lungs, and gastrointestinal tract (stomach and intestines), where they wait for their specific allergen to show up again.

When it does, the IgE captures its target allergen, causing the mast cells to release histamine and other chemicals. These, in turn, produce symptoms such as sneezing, coughing, wheezing, and tissue swelling. These chemicals also attract other inflammatory cells that worsen the reaction.

Some allergens, including certain foods (the most problematic are eggs, peanuts, wheat, fish and shellfish, milk, soy, and tree nuts), insect stings, penicillin, and latex can cause anaphylaxis, a potentially deadly reaction that can involve several organ systems. Symptoms include rash, shortness of breath, flushing, skin turning blue, lightheadedness, anxiety, stomach cramps, vomiting, and diarrhea. In severe cases, patients may become unconscious or go into shock. If an injection of epinephrine (adrenalin) is not given immediately, the person may die. It is estimated that 150 to 200 Americans die annually from anaphylaxis due to food allergies. Peanuts are the most common cause of anaphylaxis, causing 4 out of 5 of all fatal or near-fatal allergic reactions.

If you think you have an allergy, ask your doctor to refer you to an allergist, who will examine you and take your medical history. He or she may perform skin and blood tests to help determine what you're allergic to. Once the allergen (or allergens) is confirmed, you should minimize your exposure to them as much as possible. Treatment may include medications, such as antihistamines, to reduce symptoms and inflammation, or allergy shots that modify the immune response. If you're susceptible to serious allergic reactions, such as anaphylaxis, you may need to carry emergency medication (a ready-to-use epinephrine pen).

To protect yourself, always read food labels and be aware of what you're eating and drinking. Ask your doctor if you should carry emergency medications or wear medical alert jewelry. If your child has allergies, talk to her teachers and other school staff, and find out what procedures are in place in case of an allergic reaction. Also, alert your child's friends and their parents, babysitters, and camp counselors.

The contents of this health site are for informational purposes only. Always seek the advice of your physician or other qualified healthcare provider regarding any questions you may have about a medical condition.

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