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Allergies and asthma

Many people with asthma have allergies that make their asthma worse. If you have asthma, it's important to:

Allergy basics

An allergy is an abnormal reaction by your body to things that you body is sensitized to. The thing that gives you allergies is called an allergen.

Allergy symptoms

Allergies can cause many different symptoms. You may have one or many of these symptoms:

  • Itchy, watery eyes
  • Itchy, runny nose
  • Itchy skin
  • eczema - rough red skin
  • Hives - swollen mounds on your skin
  • Dark circles under and around the eyes
  • A headache that keeps coming back
  • Shortness of breath
  • Wheeze
  • Cough
  • Diarrhea
  • Stomach cramps

There are many ways allergens can enter your body:

Ingested allergens Things you eat or swallow:

Inhaled allergens: Things you breathe in:

  • Pollen from grass, trees, and plants
  • Dust
  • Animal dander from dogs, cats, mice, birds, etc.
  • Mould
  • and many others

Inhaled allergens are the most common cause of allergy problems in people with asthma. Food and drug allergies are less common.

Allergies in people with asthma

Anybody can get allergies, even people who do not have asthma. But people with asthma and allergies will have a reaction in their airways in addition to the ususal allergy symptoms (itchy, watery eyes etc.)

If you have asthma, allergens can make your airways red, swollen, and filled with sticky mucus. Your airways react as soon as you're near the allergen, and also a little while later:

Right away, you can have symptoms like wheezing and feeling short of breath. Your airways are extra-sensitive, and they can tighten as soon as you start breathing in allergens. These first symptoms can usually be relieved by a rescue inhaler (usually a blue puffer, for example, Ventolin©).

A few hours after you breathe in the allergen, you can feel a second wave of symptoms. These symptoms are caused by your airways gradually swelling (inflammation). Because there's a delay before people feel this kind of symptom, it can be hard to recognize what it was that brought on the reaction. Taking an asthma preventer medicine (for example, an inhaled corticosteroid) on a regular basis will help to prevent this reaction from happening and will help to treat the inflammation when it does happen.

What am I allergic to?

Each person has their own set of allergens. They can be allergic to one or to many things. One person might be really allergic to cats, but be fine around pollens. Another person may be really allergic to pollen and mould, but feel fine around cats. It depends on the person.

To find out what you are allergic to, see your doctor. Your doctor may refer you to an allergist (a specialist doctor who is an expert on allergies.) The allergist will ask you many questions about your medical history and your home and work environments: where you live and work, what substances you handle, what floor covering, pets, or plants are in your home, when you notice your symptoms getting worse, etc. The allergist will also do a skin prick or scratch test to see exactly what you're allergic to.

Skin prick or scratch testing: This test usually takes about 20 minutes and is done in the office of the allergist. The allergist will put tiny drops of possible allergens (things you may be allergic to) on the skin on your arm or back. The allergist may test you for many allergens at once, so you may have rows of tiny drops on your skin. The allergist will then scratch or prick your skin underneath each drop of allergen, so the allergen can get under your skin. The allergist will watch closely to see how your skin reacts to each scratch. There may be redness and swelling in some spots. Based on your skin's reaction, the allergist will be able to say what you're allergic to.

You can be mildly or severely allergic to something. You may have a small reaction when you're near one of your allergens, but a more serious reaction when you're near another. For example, you may sneeze a bit when you're cutting the lawn, but you're generally okay. However, when you're near dogs, you cough, wheeze, and feel awful. Your allergist can tell you which of your allergies are the strongest.

Common allergens and how to avoid them

Allergen What you can do
Pets - animal secretions
  • Find a loving home for your pet.
  • If you keep your pet, keep it out of your bedroom and off the furniture.
  • Have someone wash and brush your pet every week.
Dust mites - dust mites are tiny bugs that feed on skin particles that humans shed.
Dust mites like to gather in warm, moist places with lots of human skin: mattresses, pillows, carpet, and bedding.

People with dust allergies are allergic to the droppings (feces) of dust mites. To get rid of the allergy-causing droppings, you must wash out the existing droppings and kill the mites so they don't make more droppings.
  • Keep the realtive humidity in your house below 50%; dust mites don't like to live in a place with low humidity.
  • If you can, remove carpets, rugs, and heavy curtains from your bedroom.
  • Keep your bedroom free of clutter; books, boxes, and clothes lying around can all collect dust.
  • Avoid giving kids with asthma stuffed toys, as these can collect dust.
  • Vacuum rugs and carpets at least once a week.
  • Wash your bedding in hot water and dry it in a hot dryer every week. Wash stuffed toys in the same way.
  • Dust every week with a damp cloth. Wear a N95 respirator (you can purchase one at a hardware store for about $2.00) or a strip of damp, clean cotton over your face as you dust.
Pollen - grasses, weeds, flowers, trees
  • Close your windows to keep pollen out.
  • In hot weather, spend more time indoors where there is an air conditioner.
  • Avoid being outside in hot, humid weather, especially when pollen counts are highest.
  • Check the pollen counts in your area to see when the pollen you're allergic to is at its worst.
  • If you've been outside at a time of high pollen counts:
    • change into new clothes when you come indoors
    • take a shower to wash the pollen out of your skin and hair
What about "asthma-friendly" or "allergy-friendly" products - will they improve my symptoms?

You may have seen teddy bears, pillows, vacuums, mattress covers, and other products with the "asthma-friendly" or "allergy-friendly" label. Many people wonder if these products really reduce asthma symptoms, as they claim. This article from the Mayo Clinic, an American hospital, talks about products sold with an "asthma and allergy friendly" label. It provides an interpretation of what the label means and offers advice on what you should consider before buying something labeled "asthma-friendly".

My child has asthma. Should I get rid of everything in our house that could possibly cause allergies?

No! It is expensive and time-consuming to get rid of all possible triggers from your home. You only need to remove the triggers that affect your child. If your child is allergic to pollen only, you don't need to get a special dust mite cover for her bed. Instead, make sure you keep the windows closed, ask her to change into a fresh set of clothes when she comes in from outside, and take other steps that directly get rid of pollen.

Don't spend time and money in getting rid of every possible trigger. Instead, concentrate on removing the things that trigger your child's asthma.

Medicine to treat allergies

The best way to treat allergies is to prevent them - stay away from the things that you are allergic to. No treatment will work as well as simply avoiding the allergen in the first place.

If you can't avoid an allergen, you'll need treatment:

Keep taking your asthma preventer medicine, and maybe increase it - follow your doctor's directions and your asthma action plan. Your regular asthma preventer medicine, usually including a corticosteroid inhaler, reduces the swelling and redness in your airways. Take your preventer regularly to keep your airways healthy and less vulnerable to allergens.

Nasal allergy treatment: Corticosteroid sprays for your nose, antihistamines, decongestants

Allergy shots (immunotherapy) : a less common therapy that involves taking many injections of tiny amounts of the allergens (things) you're allergic to

Nasal allergy treatment

Nasal cortico-steroids

  • You'll need a prescription from your doctor
  • Spray it in your nose
  • It reduces the swelling inside your nose


  • You can buy them without a prescription (over-the-counter)
  • Counteract the histamine released in the body, which causes many symptoms
  • May cause drowsiness and may make stuffiness worse


  • You can buy without a prescription (over-the-counter)
  • Can take away the congestion (plugged up feeling in your nose and head)
  • May not work very well
  • Shouldn't be taken by people with high blood pressure and heart problems

Always read the label to find out the complete list of ingredients when buying over-the -counter medications. You can ask your pharmacist for help in understanding what the labels say.

Allergy shots

Allergy shots (immunotherapy) are one way to treat allergies. Allergy shots don't work for every kind of allergy, and they can take a while to start making a difference. Your doctor or allergist can tell you whether they think allergy shots are right for you.

Allergies shots work in the same way that the flu shot works. The idea is that if you inject an allergic person with a little bit of the thing they're allergic to, their body will learn be less sensitive to it. Allergy shot treatment can take over many years to complete.

Foods and drink that can cause allergies

These foods cause most food allergies, but other foods may also cause problems:

  • peanuts
  • fish and shellfish
  • milk
  • egg