Answers FAQ

Allergies FAQs

Reviewed by William C. Shiel Jr., MD, FACP, FACR

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Q:What is an allergy?

A:An allergy may be best described as a reaction from body's immune system to a foreign substance.Specifically, an allergy is an exaggerated reaction by our immune system in response to bodily contact with certain foreign substances. Allergic people's bodies recognize the foreign substance and one part of the immune system turns on. Allergens are substances that are foreign to the body and can cause an allergic reaction in certain people.

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Q:Anaphylaxis is a basic reaction to a simple allergen. True or False?

A:False. Anaphylaxis (anna-fill-ax-iss) is often triggered by substances that are injected or ingested and thereby gain access into the blood stream. An explosive reaction involving the skin, lungs, nose, throat, and gastrointestinal tract can then result. Although severe cases of anaphylaxis can occur within seconds or minutes of exposure and can be fatal if untreated, many reactions are milder and can be ended with prompt medical therapy.

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Q:What are examples of indoor, outdoor, food, and airborne allergens?

A:Peanuts, cockroach parts, eggs, mold spores, animal dander, pollen, seafood, tomatoes, and dust mites are some examples of allergens. In adults, the most common foods that cause allergic reactions are shellfish, such as shrimp, crayfish, lobster, and crab; nuts from trees, such as walnuts; fish; eggs; and peanuts.

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Q:The term allergic rhinitis is the proper medical term for "hay fever." True or False?

A:True. The term "hay fever" is a misnomer. Hay is not a usual cause of this problem, and it does not cause fever. Early descriptions of sneezing, nasal congestion, and eye irritation while harvesting field hay promoted this popular term. Allergic rhinitis is the correct term used to describe this allergic reaction, and many different substances cause the allergic symptoms noted in hay fever.

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Q:What are allergy medicines called?

A:Allergy medications belong to a class of drugs call antihistamines. Antihistamines are drugs that combat the histamine released during an allergic reaction by blocking the action of the histamine on bodily tissue. In other words, antihistamines do not stop the allergic reaction, but they protect the body from some allergic effects. Antihistamines frequently cause mouth dryness and sleepiness. Newer "non-sedating" antihistamines are generally thought to be somewhat less effective. Antihistamine side effects that very occasionally occur include urine retention in males and rapid heart rate.

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Q:Stinging insects can cause allergic reactions so severe, they kill this many Americans every year?

A:150. When warmer weather arrives, it is time to think about the return of stinging insects. Over 2 million Americans are allergic to stinging insects. While the severity of these allergic reactions varies greatly, they cause up to 150 deaths each year in the U.S. alone.

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Q:What causes "allergic salute"?

A:"Allergic salute" is the name for the result of persistent upward rubbing of the nose that leaves a crease. Affecting the nose, the "allergic salute" is one of seven symptoms of allergies from airborne substances and is often characteristic of a person suffering from allergic rhinitis (hay fever). Other allergy symptoms include sneezing often accompanied by a runny or clogged nose; coughing and postnasal drip; itchy eyes, nose and throat, and allergic shiners (dark areas under the eyes).

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Q:Allergies can cause conjunctivitis. True or False?

A:True. Inflammation of the conjunctiva of the eyes that is caused by allergy is referred to as allergic conjunctivitis. Eye allergies mainly involve the conjunctiva, the tissue lining (mucus membrane) covering the white surface of the eyeball and the inner folds of the eyelids. The conjunctiva is a barrier structure that is exposed to airborne particles of the environment. These particles can sometimes stimulate an allergic response in the conjunctiva. The conjunctiva is rich in blood vessels and cells of the allergic response called mast cells (histamine-releasing cells).

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Q:Which of these symptoms indicates a cold rather than an allergy?

A:Mucus with yellowish nasal discharge would indicate a cold, not an allergy. Also, cold symptoms such as sneezing, runny nose and congestion often appear one at a time. In allergy sufferers, these symptoms present at the same time and continue with exposure to the allergen. Sneezing is more common with allergies and can cause a person to sneeze multiple times in a row. Allergies tend to produce a clear, thin watery discharge. Colds can produce fever and yellowish thick discharge. Additionally, colds generally appear during the winter months, while allergies are more common in spring and fall.

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Q:What is animal or pet dander?

A:The term "dander" refers to microscopic particles of skin. Dander is comprised of tiny scales of skin shed from human or animal skin and hair. Dander floats in the air, settles on surfaces and makes up much of the dust found in any home. Cat dander is a classic cause of allergic reactions.

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Q:What is pollen?

A:Pollen is a dry protein from trees, grass, flowers, and weeds. It is a heavy, waxy substance carried by flying insects and a grainy, potent, histamine-producing allergy trigger. Pollen is commonly spread by the wind. Most people have little contact with the large, heavy, waxy pollen grains of many flowering plants because this type of pollen is not carried by wind but by flying insects such as butterflies and bees. The light form of pollen can lodge in the mucus membranes that line the nose and in other parts of the respiratory tract, causing irritation and histamine allergic reactions.

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Q:Which is disease is commonly associated with a gluten allergy?

A:A person who is allergic to gluten may have celiac disease. This means the body produces and allergic reaction to the protein in wheat, rye, and barley. Gluten is the protein found in wheat, rye, and barley. Gluten is a basic component of most of the grain-based products we eat, such as cereals, breads, and pasta. For those who are allergic to the substance, consuming gluten can result in abdominal pain, gas, bloating and diarrhea. More serious gluten intolerance is called celiac disease, which causes significant injury to the small bowel, particularly the duodenum.

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Q:On average, how many Americans suffer from allergies?

A:20% of Americans suffer from allergies. At least one out of every five (20%) Americans suffers from allergies.

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Q:How are allergies diagnosed?

A:Allergies are diagnose through blood tests and allergy skin tests. Diagnosing allergies starts with a doctor's exam, however, allergy skin tests and blood tests are commonly used to identify the substances that are causing allergy reactions.

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Q:An allergic reaction can produce urticaria. Urticaria is a common term for what?

A:Urticaria is the medical term for hives. Hives are raised, itchy areas of skin that are usually a sign of an allergic reaction. Hives can be rounded or flat-topped but are always elevated above the surrounding skin. Hives cause a local swelling of the skin. Hives are usually well-defined, but may bunch together and will blanch with pressure.

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