The Connection Between Allergies and Asthma

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Because asthma and allergies are so common and frequently occur together, most parents may want to know about preventing or avoiding these conditions.

Allergy Insight

“Allergen” is the word that doctors use to describe a substance in the environment to which our bodies may react with an allergic or asthmatic reaction. Common allergens include pollen, animal dander, mold, dust mites, latex, certain foods, insect bites and stings, certain plants, and medications.

We are all exposed to at least some allergens all the time. But, most of us can encounter these troublemakers without experiencing any symptoms at all. For these people, their body simply does not react to allergens. However, for millions of people, an excessive immune response to allergens triggers a cascade of unpleasant symptoms. These symptoms are sometimes mild, but they can be severe, or rarely, even fatal. Allergic symptoms most commonly include itching of the eyes, throat, or skin, sneezing, nasal congestion, coughing, wheezing, or rash.

Typically, allergic substances enter the body in one or more of the following ways:

• Absorption through the skin (latex)
• Inhalation through the mouth or nose (pollen or dust mites)
• Ingestion (foods or medications)
• Injection (insect bites and stings)

Asthma Insight

Asthma is a condition in which the lungs react to some kind of irritation with mucous production and airway narrowing from muscle contraction and inflammation along the breathing pathway. This reaction may occur moments after exposure to an irritant or after several hours have passed. Allergy is a common cause of asthmatic reactions, but similar symptoms can be produced by non-allergen sources, such as chemical or lung irritants or viral infections. An asthma episode usually includes difficulty breathing, wheezeing coughing, or other respiratory symptoms. Asthma is usually controllable with treatment. In between “attacks,” or after treatment, the lungs usually return almost completely to normal.

Exposure to tobacco smoke may trigger asthma in children because smoke is an irritant. Other triggers include exercise, cold air, and allergens. The allergens that most commonly cause an asthma episode are dust mites, mold, pollen, and animal dander. Food allergies can also trigger an asthma episode in some people. Foods like shellfish and peanuts can be asthma triggers.

The Allergy-Asthma Connection

It is possible for your children to have allergies but not asthma, or to have asthma without allergies, but the two conditions often occur together. Eczema and hay fever are common conditions associated with asthma.

For some people, the connection between these conditions lies in the similar biologic responses they cause to otherwise harmless environmental triggers. If you have allergies and/or asthma, your body is attempting to protect itself from substances it perceives to be dangerous. Unfortunately, this protective reaction triggers the release of body chemicals that cause results like sneezing, congestion, itchy red eyes, skin rash and/or wheezing, shortness of breath, and cough. With allergic asthma, the allergic reaction may be confined to the airways, or may include other forms of allergy that affect the skin, eyes, or ears.

Putting Knowledge Into Action

You cannot change your child's genetics, but you can do a number of things to safeguard your home and family against allergies and asthma. While developing allergies and/or asthma may be inevitable for some, following these tips may lessen the severity and frequency of episodes for people who are at high risk:

• Control exposure to smoke—Do not smoke at all. But, if you must smoke, do so outside. Never smoke in a car that children ride in, even if your child is not in the car at the time. Wood smoke may also be an asthma risk; avoid wood heating. Make sure that gas heaters and stoves are vented to the outside. These appliances produce combustion products that can irritate the lungs.
• Control exposure to dust mites—Dust mites are microscopic creatures that are found in large quantities in your home. They tend to live in bedding, but are far too small to be seen. Strategies to reduce exposure to mites include:
  • Wash all linens in hot water every seven days.
  • Vacuum carpeting and upholstered furniture frequently using a vacuum cleaner with a “HEPA” filter.
  • Keep indoor relative humidity below 50%.

Controlling exposure to pets may be an option, though this is age related and often debated because evidence is inconsistent. In some studies, exposure to pets at a very young age was associated with less risk of allergies.

There is little evidence to support that using zippered plastic covers on pillows and mattresses helps control dust mite exposure.

There are other exposures you might want to avoid. Be aware that latex paints, chipboard furniture, and some rugs may release certain chemicals that can cause wheezing in children. If you can, choose to live away from busy highways. This will reduce any risk from automobile and truck exhaust.

Other sources of allergies include cockroaches, rodents, and mold. Careful cleaning of bathrooms and repairing leaky pipes can help reduce mold from growing.

Food is an important trigger for some children. Breastfeeding may help reduce the incidence of allergies, as well as asthma.

Knowing the underlying types, causes, and triggers of both asthma and allergies is the foundation of putting effective prevention and treatment strategies into action.

Revision Information

• Reviewer: Michael Woods, MD
• Review Date: 06/2016
• Update Date: 06/06/2016