Allergy

An Allergy is an abnormal reaction by the immune system to a substance that would normally be harmless. This disorder of the immune system is characterized by excessive activation of certain white blood cells by a form antibody causing an extreme inflammatory response.  Strictly speaking, it is just one of the 4 types of hypersensitivity and is designated as immediate or type 1 hypersensitivity.


There are a number of common Allergy reactions including cehayfever.gif

  • eczema
  • hay fever
  • hives
  • asthma
  • reaction to the venom of stinging insects such as bees and wasps
  • reactions to cats and dogs
  • food intolerance

Many people are affected by mild allergies such as hay fever with more than 39 million Americans experiencing its symptoms to some degree. Hay fever or allergic rhinitis can cause symptoms such as sneezing, irritated, runny nose or blocked nasal passages, itching and redness of eyes, watery eyes or allergic conjunctivitis.  This Allergy is usually triggered by airborne pollens, dust, dust mites or mold spores. These triggers are usually seasonal and can be normally controlled with medications.



Environmental conditions are only part of the possible cause of severe allergic responses in some people. Other Allergy triggers may be:

  • dietary
  • medications
  • animals
  • insect stings
  • foods

Each of these triggers can cause a different style of allergic reaction displaying differing symptoms. For instance a food intolerance could cause abdominal pain, bloating, diarrhoea and vomiting as well as angiooedema and itchy or swollen skin as part of hives. A food Allergy rarely causes respiratory reactions or rhinitis, however reactions to airborne allergens and allergies caused by animals or insect stings and can lead to these asthmatic symptoms. These are caused by bronchoconstriction a narrowing of the airways and an increase in the production of mucus in the lungs leading to shortness of breath, coughing and wheezing.


Allergies play a major role in the onset of conditions such as asthma with many of the triggers being common.  Environmental and dietary allergens as well as reactions to insect stings and medicines such as aspirin and antibiotics can produce a systemic allergic response called anaphylaxis. Severe anaphylactic reactions can be life threatening.  Reactions of this nature can affect the respiratory and circulatory systems and depending on the severity can cause cutaneous reactions, edema, hypertension, coma, bronchoconstriction and potentially cause death.


Allergy testing can identify whether a person is likely to react to certain triggers. These usually take the form of either skin tests or blood tests. Once an Allergy is identified a management plan can be established to help cope with the condition. This can be as simple as an allergen avoidance strategy, the use of antihistamines, steroids or other oral medications or desensitization by immunotherapy and targeted therapy.  A severe Allergy reaction may require an injection of epinephrine to control the symptoms and sometimes save the life of the person having the reaction.


Although allergies are relatively common it is usually fairly easy to identify and manage most forms of the more common types of Allergy.