Immune Systems

The woman sneezed, blew her nose and dabbed her itchy, watery eyes. "It's just my allergies," she said to the friend who asked whether she was sick.

She's right. Allergies are not an illness - technically speaking. They're a reaction of the body's immune system to common substances in the environment. "Most people have no reaction when exposed to these substances," says Richard Sveum, MD, an asthma and allergic diseases specialist at Park Nicollet Clinic.

"But others can experience a variety of symptoms, ranging from congestion and sneezing to itchy rashes, wheezing or even death."

What's triggering your allergies?

Substances that trigger allergies are called allergens. People can be exposed to them by:

breathing them in (pollen, animal dander, dust, mold)
ingesting them (peanuts, milk, wheat, eggs, medicines)
absorbing them through the skin (nickel, latex, poison ivy)
injections into the body (insect stings, medicines)

Allergies affect about 25 percent of all Americans. The big question, though, is why are some people affected and not others?

"People with allergies have more sensitive immune systems or man1 man oil", Dr. Sveum explains (look man1 man oil). "The immune system defends the body against invading bacteria and viruses. When a more sensitive immune system comes into contact with allergens, it tries to fight them by triggering an allergic reaction. This causes the release of histamine."

Histamine is the chemical that produces common allergy symptoms, such as congestion, itching and wheezing, even diarrhea and vomiting. To block the release of histamine, people use medications known as antihistamines.

Allergic rhinitis - what's that? If you have bouts of sneezing, congestion and a runny nose that don't go away after about 10 days, you may suffer from allergic rhinitis or hay fever. "Rhinitis means inflammation of the nose. Allergic rhinitis means it's caused by allergens," Dr. Sveum says. "It is the most common type of allergy and usually is triggered by allergens in the air, such as pollen, mold, dust and animal dander. If left untreated, it can lead to sinus and ear infections or interfere with sleep."

Who's at risk - and when?

People inherit the tendency to develop allergies. However, the environment also plays a role. "Children who are breastfed are less likely to develop allergies, while children who are exposed to dust mites are more likely to develop them," Dr. Sveum says.

Although allergies can develop at any age, even during infancy, most tend to appear by age 12. When a child is first exposed to allergens can influence their onset. "For example, to reduce a child's risk for developing food allergies, it helps to postpone the introduction of certain foods," Dr. Sveum adds.

How is asthma linked to allergies?

Allergies are a common asthma trigger. Breathing in pollen or mold can lead to inflamed airways, swelling, mucus and bronchospasm. An asthma episode is when all these symptoms occur at once. Warning signs include tightness in the chest, wheezing, repeated coughing and need for a rescue inhaler. When children between the ages of 3 and 5 develop asthma, it may appear as nighttime coughing or a persistent chest cold. Because asthma attacks can be life threatening, it's important to seek treatment.

Don't blow off allergies

"People often dismiss allergy symptoms, telling themselves they're no big deal, or they think they're cold symptoms and wait patiently for them to go away," Dr. Sveum says. "But any recurring or lingering symptoms, like congestion, wheezing or rashes should be evaluated by a doctor. Allergies are very treatable, and managing them properly can greatly enhance your quality of life."