Allergies and Asthma

Medically Reviewed by Sabrina Felson, MD on October 30, 2021
7 min read

Asthma attacks (worsening of asthma symptoms) can be triggered by allergies, which can temporarily increase the inflammation of the airways in a susceptible person.

An allergy is the immune system's reaction when exposed to what is otherwise a harmless substance, such as plant pollen, mold, or animal hair, skin, or saliva. The immune system acts as a body defense, yet for people with allergies, the immune system treats these things, called allergens, as if they are harmful, causing a disruption to normal body functions. Allergens are what trigger a series of reactions by the immune system during an allergic reaction.

Inhaled allergens. The most important allergens for people with allergic asthma appear to be those asthma triggers that are inhaled. Hay fever or seasonal allergic rhinitis occurs when a person comes in contact with an allergen or a substance that they are sensitive to. Common inhaled allergens include:

Medical experts recommend that all people with allergies and asthma try to identify possible inhaled allergens that may trigger asthma symptoms.

If you can avoid coming in contact with the substance you are allergic to (allergen), you may be able to prevent symptoms of an asthma attack.

Food allergies. Food allergies rarely cause asthma, yet they can cause a severe life-threatening reaction called anaphylaxis. The condition can lead to symptoms that include trouble breathing, wheezing, an itchy rash, low blood pressure, and vomiting. The most common foods linked with allergic symptoms are:

  • Eggs
  • Cow's milk
  • Peanuts
  • Tree nuts (such as almonds, pecans, and walnuts)
  • Soy
  • Wheat
  • Fish
  • Shrimp and other shellfish

Food preservatives can also trigger allergic and asthmatic reactions. Additives, such as sodium bisulfite, potassium bisulfite, sodium metabisulfite, potassium metabisulfite, and sodium sulfite, are often used in food processing or preparation and may be found in foods such as:

  • Dried fruits or vegetables
  • Potatoes (packaged and some prepared)
  • Wine and beer
  • Bottled lime or lemon juice
  • Shrimp (fresh, frozen, or prepared)
  • Pickled foods

If you suspect that certain foods may be the cause of your asthma, discuss it with your doctor. You can have allergy skin testing to find out if you are allergic to these foods.

Avoid allergy triggers at restaurants by asking about preparation methods when dining out. Choose fresh foods rather than prepared or processed foods. If you have severe asthma attacks or anaphylaxis, carry two epinephrine injection kits with you at all times.

If you have allergies and asthma, avoid the substance you are allergic to. Here are some tips to help you avoid some of the most common allergens and prevent asthma attack symptoms.

Dust mites

  • Encase pillows, mattresses, and box springs with allergen-proof, zippered covers.
  • Wash all bedding in hot water once a week.
  • Noncarpeted flooring is best. If you cannot get rid of your carpeting, vacuum often with an HEPA filter. Wear a mask while vacuuming. If your child has asthma, do not vacuum while they are in the room. Products that eliminate dust mites from carpeting (such as Acarosan) can be purchased. Your asthma care provider can give you information about these products.
  • Avoid curtains and drapes. Use plain window shades instead of mini-blinds. Washable curtains should be washed in hot water every 2 to 4 weeks.
  • Dust all surfaces with a damp cloth often, including lampshades and windowsills.
  • Keep clutter under control. Toys and books should be stored in enclosed bookshelves, drawers or closets.
  • Replace traditional stuffed animals with washable stuffed animals.
  • Keep all clothing in drawers and closets. Keep drawers and closets closed.
  • Cover air ducts with filters. Change these when soiled.
  • Pillows and bedding should not contain feathers.
  • Keep indoor humidity low (below 50%). Use a dehumidifier if needed.
  • Regularly change filters on heaters and air conditioners.

Mold and mildew

  • Air out damp, humid areas frequently. Run a dehumidifier to keep humidity between 35% and 45%.
  • Use air conditioners when possible.
  • Clean bathrooms regularly using products that kill and prevent mold. Use exhaust fans to vent steam. Do not carpet the bathroom.
  • Keep indoor plants out of bedrooms.
  • When painting, add mold inhibitor to paint to prevent mold from growing.
  • Avoid sources of outdoor molds, such as wet leaves or garden debris.
  • To clean visible mold use a cleaning solution containing bleach (1 ounce per quart of water).
  • Wash shower curtains and bathroom tiles with mold-killing solutions.
  • Avoid areas where molds may collect, including basements, garages, crawl spaces, barns, and compost heaps. Have someone else clean these areas often.
  • Air out damp clothes and shoes (in the house) before storing.
  • Remove laundry from the washing machine promptly. Don't leave wet clothes in the washer where mold can quickly grow.
  • Don't collect too many indoor plants, as soil encourages mold growth.
  • Store firewood outside.
  • Avoid raking leaves or working with hay or mulch if you are allergic to mold.

Insects

Many homes and apartments have cockroaches and other insects. Some people with asthma are allergic to a protein in their droppings. To control these allergens in your home:

  • Use roach baits or traps.
  • Insect sprays can be used, but should only be sprayed when no one is at home. Before you or your child returns home after spraying, make sure that your home has been aired out for a couple of hours.
  • Because cockroaches thrive in humid environments, fix water leaks in and around your home.
  • Cover food in lidded or sealed containers. Clean dishes after eating. Sweep floors after you have eaten.

Pollen

Pollen is a fine powdery substance, typically yellow, that is released by flowering plants as part of their propagation (reproduction). Pollens are difficult to avoid because they cannot be eliminated from the atmosphere. Plants have different periods of pollination, which varies little from year to year. Yet the type of weather affects the amount of pollen in the air with hot, dry, and windy weather causing more pollen in the air. In general, pollen season starts from February to October.

You can lessen your or your child's exposure to pollen by:

  • Limiting your or your child's outdoor activities during times of high pollen, such as early morning.
  • Having yourself or them wear a hat outdoors, washing your or their hands and face when you or they come inside, and having them or yourself change their or your clothes after being outside.
  • Staying indoors during dry or windy days when pollen counts are high.
  • Keeping windows closed during pollen seasons.
  • Using air conditioning if possible.
  • Minimize walks in wooded areas or gardens.
  • Check the forecast. Stay indoors as much as possible on hot, dry, windy days when pollen counts are generally the highest.
  • Wear a mask (such as an inexpensive painter's mask) when mowing the lawn if you are allergic to grass pollen or mold. Avoid mowing and being around freshly cut grass if possible.
  • Wear a mask when gardening, as flowers and some weeds release pollen and can cause allergy symptoms.
  • Take a shower after being outdoors. Also, wash your hair, and change your clothes to remove pollen that may have collected in your clothes and hair.
  • Avoid hanging clothes or linens out to dry, as pollen and molds may collect in them and can make your allergies worse.

Pet dander

  • It is best not to have pets if you or your child is highly allergic to pet dander.
  • Long visits to friends and family who own pets should be avoided. If you do visit, make sure you or your child takes asthma or allergy medicines beforehand. Keep exposure to the pets to a minimum.
  • If you must have a cat or dog in the home, restrict its living area. It should not be allowed in your or your child's bedroom at any time. If possible, keep the pet outdoors.
  • Wash your pet weekly.
  • Remove as much carpeting as possible. Animal dander deposits in the carpet and stays there, even after the pet is gone from the home.

For asthma prevention at school when your child has allergies and childhood asthma:

  • Discuss their allergies and asthma with school personnel.
  • If your child has food allergies, discuss them with school officials, teachers, and lunchroom staff.
  • Educate your child about their allergies and asthma early, so your child can learn to avoid situations where they may eat food that will trigger an allergic reaction. Arrange for an epinephrine kit to be left at the school, and make sure school officials (and your child, when they are old enough) are able to use it correctly and without hesitation should symptoms arise.
  • Inform school personnel about the asthma treatments your child is taking, and make arrangements to leave necessary medication at school.
  • Encourage sports participation, but inform coaches of medicines that may need to be taken before activities to prevent exercise-induced asthma.

You can train your immune system to not overreact to allergy triggers. Doctors do this by giving you allergy shots (immunotherapy) for asthma. An allergy shot is a small amount of the substance that causes your allergy. By giving repeated shots of the substance over a period of time, your immune system eventually stops causing the allergic reaction. Ask your doctor if you are a candidate for allergy shots for preventing asthma.