Glossary of Allergy and Asthma Terms


by Robert W. Hellmers, M.D.

Allergy Terms

Systemic anaphylaxis. The most severe type of allergic reaction. As a result of exposure to an allergen, histamine is released systemically (throughout the body) affecting several body systems including the respiratory system, the skin, the circulatory, and/or the nervous system. Some common symptoms of systemic anaphylaxis are trouble breathing, severe swelling of the throat, nausea, itching, rash, irregular heartbeat, and pale, cool skin. This is a life-threatening condition and should be treated immediately.

Antihistamine. A medication that blocks the action of histamine during an allergic response, preventing itching, sneezing, runny nose. Antihistamines are most often used to treat symptoms associated with allergies, but may sometimes be used to treat colds because they dry the mucous membranes.

Decongestants. Decongestants work by shrinking dilated blood vessels to normal size, allowing air to pass through. They also help relieve runny nose and post nasal drip, which can cause a sore throat. Decongestants can be taken orally or used as nose drops or sprays. Decongestants are also used to treat symptoms of both allergies and colds.

New once-a-day, timed release antihistamine/decongestant combination drugs are now available for convenience.

Dermatitis. Inflammation of the skin with itching, redness, and sores. Dermatitis is often an allergic reaction of allergens like poison ivy or latex.

Histamine. When a person susceptible to allergies is exposed to an allergen such as pollen, antibodies signal the mast cells to release a flood of chemicals including histamine against the harmless invader. Histamine is responsible for the swelling, itching, and other irritations familiar to allergy sufferers.

Perennial allergic rhinitis. Nasal allergy symptoms that occur year-round. People with this condition are sensitive to allergens and environmental irritants such as dust mites, animal dander, and molds that are around throughout the year.

Immunotherapy. Also called “allergy shots,” this is a preventative treatment for allergies and substances such as pollen, house dust, mites, molds, and stinging insect venom. Immunotherapy involves injecting the patient with gradually increasing doses of the substance to which the person is allergic. By gradually increasing the patient’s exposure to the allergen, the immune system becomes less sensitive to that substance. Over time, allergy symptoms can be reduced when the patient is exposed to that particular allergen.

Mast cell. Mast cells play an important role in the body’s allergic response. These cells are found in most body tissues. During allergic response, an allergen such as pollen stimulates the release of antibodies, which attach themselves to mast cells. Then, every time the person with allergies is exposed to the same allergen, the mast cells release substances such as histamine into the tissue. Histamine is the primary chemical responsible for allergic symptoms.

Asthma Terms

Asthma attack. In response to a trigger in the environment, the lungs of a person with asthma undergo three types of changes that make breathing – especially inhaling – difficult. The changes are inflammation of the airways (i.e., swelling of the lining of the airways), bronchoconstriction (i.e., tightening of the muscles around the airways causing passages to narrow), and increased mucus production in the airways.

Asthma Prevention Medicines

Inhaled corticosteroid: An anti-inflammatory drug used to reverse or prevent airway inflammation that caused asthma.

Inhaled cromolyn or nedocromil: An asthma medicine that helps stabilize airways, making them less sensitive to allergens and exercise.

Long-acting bronchodilator: An asthma treatment used to prevent bronchoconstriction.

Asthma Relief Medicines

Short-acting bronchodilator: Medication that works quickly to open airways in the lungs to make breathing easier. Primarily used to stop symptoms of acute asthma attack or to prevent exercise-induced symptoms.

Environmental controls. Altering your environment in order to prevent allergy and asthma attacks. Examples of environmental controls include installing high-efficiency air filters, encasing bedding such as mattress and pillows in special material, removing or treating carpeting, keeping pets outdoors, and avoiding perfumes, colognes, and tobacco smoke.

Lung function. The evaluation of how well your lungs deliver oxygen and eliminate carbon dioxide from the body compared to what is normal for you as an individual. Before and during an asthma attack, lung function decreases because of increased mucus production, constriction, or tightening of the muscles around the airways caused by inflammation, or swelling of the airways. Decreased lung function is associated with a reduction in oxygen delivery to the brain, body organs, and tissues.

Peak flow meter. This device measures air flow out of the lungs in a given period of time, which is one of the factors involved in lung function. Used regularly, a peak flow meter can help detect an asthma attack hours or even days before it happens. Regular daily readings in the morning and evening will help your doctor determine how well your asthma management plan is working. Use of a peak flow meter is recommended by the National Institute of Health.

Posted in: Allergy Terms

Allergy and the Environment