What is an Allergy?

The job of the bodies immune system is to identify foreign substances (such as viruses and bacteria) and get rid of them. Normally, this response protects us from dangerous diseases.

If you have allergies, you have a supersensitive immune system which reacts to harmless substances, like plant pollen, dust mites, or animal dander. These substances are calledallergens. Your immune system’s overreaction is what causes your allergy symptoms.

Super-sensitive immune systems tend to run in families. Although no one is born with allergies, you can inherit the tendency to develop them. One thing is true for all allergic people: the more often and the more directly you come in contact with an allergen, the more likely you are to develop an allergy to it.

Allergies usually begin to develop in childhood, although they can show up at any age. The most common allergies among infants are food allergy and eczema (patches of dry skin). In older children and adults, allergic rhinitis (hay fever) is more common. As some children get older their symptoms decrease, only to reappear later in life.

The most common kind of allergy involves a gradual build-up of proteins called IgE antibodies. For example, the first time you pet a cat, your body may overreact and produce IgE antibodies in response to the animal’s hair. The antibodies attach to mast cells in your nasal passages and remain in your body. Each time you get near a cat, your body will produce more cat hair IgE antibodies. At some point–in trying to protect you from this perfectly harmless cat hair–your mast cells will release molecules such as histamine and lipid mediators. These molecules cause your allergy symptoms such as sneezing, watery eyes, and a runny nose. Over time, cat hair has become an allergen for you.

Depending on your allergy, your symptoms may range from runny nose to itchy hives to a serious, life-threatening reaction called anaphylaxis. Anaphylaxis causes swelling of body tissues, vomiting, cramps, and a drastic drop in blood pressure. It occurs most often in people who are allergic to insect stings, drugs, and certain foods.

Common Allergens

  • Dust mites and their waste
  • Hair and saliva of animals with fir or feathers
  • Cockroaches and their waste
  • Weed, grass and tree pollens
  • Mold and mildew spores
  • Stinging insects such as bees, wasps and hornets
  • Drugs such as penicillin
  • Foods such as eggs, milk, nuts and seafood
  • Plants such as poison ivy and poison oak
  • Ingredients found in dyes, cosmetics, and latex

Allergic rhinitis
 is an inflammation of the mucus membranes in the nose, throat, sinuses, and/or ear passages which occurs when you inhale an allergen. Common symptoms include nasal stuffiness, sneezing, nasal itching, clear nasal discharge, and itching of your ears and/or roof of the mouth. Your symptoms may be season or year-round.

Red, itchy, watery eyes are typical of allergic conjunctivitis (eye allergy).

Symptoms of atopic dermatitis (eczema) include red, itchy, dry skin, usually on elbows, knees, and skin folds.

Urticaria  are itchy welts which may appear on any part of your body.

Contact dermatitis is an itchy rash which breaks out where an allergen has touched your skin. Poison ivy is one common culprit.

Try keeping a record of when, where, and under what circumstances your reactions occur. This can be as easy as jotting down notes on a calendar. If the pattern still isn’t clear, make an appointment with your doctor.

Doctors diagnose allergies by using the following three steps:

  • Personal and medical history.
  • Physical examination.
  • Tests to determine your allergens.

Good allergy treatment is based on the results of your allergy test, your medical history, and the severity of your symptoms. Treatment includes three parts:

  1. Education about avoiding your allergens
    The best way to prevent allergy symptoms and minimize your need for allergy medicine is to avoid contact with your allergens as much as possible. 
  2. Medication
    Antihistamines and decongestants are the most common medicines used for allergies. They come in both prescription and non-prescription form. Newer antihistamines which cause less drowsiness are available by prescription –  some over the counter in the UK,Cromolyn sodium and corticosteroids are prescription medicines for the treatment of allergic rhinitis and allergic conjunctivitis. Topical corticosteroids are prescribed for atopic dermatitis.


  3. Allergy Shots (Allergen Immunotherapy or Desensitization Therapy)
    When it is not possible to avoid exposure to the things that make you allergic, allergen immunotherapy can often prevent allergy symptoms. This treatment involves receiving increasingly higher doses of your allergen over time. This can be effective for people with life-threatening reactions to insect stings, and for some people with allergic rhinitis and allergic conjunctivitis. It is not as effective for allergies to food or feathers, nor is it effective for hives. This treatment is quite rare nowadays as some patients have died due to anaphylactic reactions.

The answer is “yes” if…

  • You can’t avoid your allergens and non-prescription allergy medicines don’t work or don’t give relief for any length of time.
  • Your are taking non-prescription allergy medicines for more than 3 months (total) in a year.
  • You are having side effects from non-prescription allergy medicines.
  • Your allergies are year-round.
  • Your symptoms are severe enough to disrupt school, work, or your lifestyle.

Helping you cope with your Asthma