20 Questions About Allergy-Triggered Asthma

Courtesy of Dr. Robert Nathan

Robert A. Nathan, MD, is a clinical professor of medicine at the University of Colorado Health Sciences Center and director of the Asthma and Allergy Associates and Research Center in Colorado Springs, Colo.

Q: "What's the difference between asthma that is due to allergies and asthma that is not?"

A: "Allergic asthma is an overreactive immunologic response that occurs because a person's body makes too much of an immune system component called immunoglobulin E (IgE). People with allergic asthma are bothered by common allergens like animal dander, dust mites, pollen, mold, or cockroaches, and they are often allergic to more than one of these things.

When a person has asthma that isn't related to allergies, but is instead triggered by facto rs that act directly on the lungs, such as infections, exercise, cold air, pollution, and stress, they have non-allergic asthma. Many people with asthma have a combination of non-allergic and allergic asthma. Of the nearly 19 million adults in the United States with asthma, about half have asthma that's related to allergies. But just 20% of adults with asthma have symptoms triggered by just allergies alone."

Q: "How can you tell if your asthma is due to allergies?"

A: "First and foremost is the medical history. If a patient says he only has symptoms when he's near a cat or dog, for example, or only during pollen season, it's likely to be due to allergies."

Q: "How can you know for sure what's triggering your asthma?"

A: "Skin tests, also known as 'skin prick tests,' are the gold standard. They involve putting a tiny amount of the allergen into the very top layer of your skin. The area will then swell, itch, and turn re d if you are sensitive to that allergen."

Q: "Do you need to see an allergist or a pulmonologist to be diagnosed with allergic asthma, or can your primary care doctor do the job?"

A: "Pulmonologists deal with a myriad of lung diseases, but allergists deal primarily with asthma and other allergic conditions, so they are better prepared to diagnose and treat allergic asthma. Most importantly, we're trying to identify triggers and help the patient understand how to deal with those triggers. The primary care physician may suspect that asthma is related to allergies, but it's the allergist who can confirm the diagnosis by using objective measures, like the skin test."

Q: "Is asthma harder or easier to treat if it's due to allergies?"

A: "Avoidance is the main way to treat any allergic disease. In a way, it's easier to treat allergic asthma than non-allergic asthma, because you can just stay away from the allergen. But this depen ds on what the allergen is, and how sensitive you are to it. The ace in the hole that patients with allergic asthma have that patients with non-allergic asthma don't have is immunotherapy, or as it's more commonly known, allergy shots. It is potentially curative, whereas medication can only address symptoms."

Q: "Does allergic asthma ever get better on its own?"

A: "While some children will 'grow out of' their allergic asthma once they reach puberty, it's exceedingly rare for an adult's disease to go into remission."

Q: "Can allergic asthma be life threatening?"

A: "It's rare but certainly possible, depending on the extent of exposure, how bad an attack gets, and how long it takes for you to get treatment. Every year, 3,500 Americans die from asthma, and some will have had allergy-induced asthma."

Q: "Will allergy shots help? What do they entail?"

A: "Allergy shots, or immunotherapy, can definitely help, but they're a major commitment. For allergy shots to be effective, a person needs to visit an allergist regularly for several years. And while insurers typically cover immunotherapy, copayment costs can add up.

At first, a person undergoing immunotherapy will go to the allergist once or twice a week, for three to six months, receiving slightly larger amounts of the allergen with each visit. The shot itself is very quick, but patients must wait in their doctor's office for 20 to 30 minutes to see if a reaction occurs. After this initial phase, the patient's visits are spread out to every two to four weeks. This maintenance phase can take two to five more years. A person is considered to be free of an allergy if he or she can go for two years without symptoms, which in essence means not having to take allergy medication."

Q: "At what age do people typically develop allergic asthma?"

A: "Usually symptoms start before age 10, but a person c an develop allergic asthma at any point in his or her life. It's rare for someone in their 60s or older to develop allergic asthma for the first time."