The word allergy is derived from the Greek words "allos", meaning different or changed and "ergos" meaning work or action. Allergies are abnormal reactions of the immune system that occur in response to otherwise harmless substances.


Allergy-producing substances are called "allergens". When an allergen comes in contact with the body, it causes the immune system to develop an allergic reaction in persons who are allergic to it. When you inappropriately react to allergens that are normally harmless to other people, you are having an allergic reaction and can be referred to as allergic or atopic. 


The severity of allergies varies from person to person and can range from minor irritation to anaphylaxis - a potentially life-threatening emergency.

Symptoms of allergies


Your immune system produces substances known as antibodies. Some of these antibodies protect you from unwanted invaders that could make you sick or cause an infection. When you have allergies, your immune system makes antibodies that identify your particular allergen as something harmful, even though it isn't. When you come into contact with the allergen, your immune system's reaction inflames your skin, sinuses, airways or digestive system.


  • Airborne allergens cause the sneezing, runny nose, and itchy, bloodshot eyes of hay fever (allergic rhinitis). Airborne allergens can also affect the lining of the lungs, causing asthma, or the conjunctiva of the eyes, causing conjunctivitis (pink eye).
  • Allergens in food can cause itching and swelling of the lips and throat, cramps, and diarrhea. When absorbed into the bloodstream, they may cause hives, non-inflammatory swelling of the skin, mucous membranes, organs, and brain (angioedema). Some food allergens may cause anaphylaxis, a potentially life-threatening condition marked by tissue swelling, airway constriction, and drop in blood pressure.
  • In contact with the skin, allergens can cause reddening, itching, and blistering, called contact dermatitis. Skin reactions can also occur from allergens introduced through the airways or gastrointestinal tract. This type of reaction is known as atopic dermatitis.
  • Injection of allergens, from insect bites and stings or drug administration, can introduce allergens directly into the circulation, where they may cause system-wide responses (including anaphylaxis), as well as the local responses like swelling and irritation at the injection site. Common allergens 
  • The most common airborne allergens are the following: plant pollens, animal fur and dander, body parts from house mites (microscopic creatures found in all houses), house dust, mold spores, cigarette smoke, solvents, cleaners
  • Common food allergens include the following: nuts, especially peanuts, walnuts, and Brazil nuts, fish, mollusks, and shellfish, eggs, wheat , milk, food additives and preservatives 
  • Common causes of contact dermatitis include the following: poison ivy, oak, and sumac, nickel or nickel alloys, latex
  • Insects and other arthropods whose bites or stings typically cause allergy include the following: bees, wasps, and hornets, mosquitoes, fleas, scabies.

Prevention and treatment

There is known no cure for allergies, but there are things you can prevent an allergic reactions;

  • Avoiding known allergens.
  • Use of medications such as anti-histamines that specifically prevent allergic reactions.
  • Steroids that modify the immune system in general. 
  • Medications such as decongestants that relieve the symptoms. Many of these medications are taken by mouth, though epinephrine, which is used to treat anaphylactic reactions, is injected.
  • Immunotherapy- uses injected allergens to desensitize the bodys' response. Eating healthy, having enough rest and obey all the basic rules of Nutrition.


Simple Ways to Reduce Allergens

Take the following actions to cut down on allergens in your home:

  • Keep your home dry and well ventilated by opening windows for at least one hour twice a day and keep vents open, particularly in kitchens and bathrooms
  • However, if you get hay fever keep the windows closed as much as possible during the peak of the pollen season
  • Don't dry clothes indoors, especially in your bedroom or living room
  • Increase the ventilation if your home is very humid - a dehumidifier might help
  • Keep pets outside as much as possible or limit them to one room only, preferably one without carpeting.
  • Don't allow pets into bedrooms, as skin flakes (dander) can remain airborne for long periods. Cat dander allergen can also be carried around on clothing into schools or the workplace, try also to wash them regularly.

Information Source Links

  • P. A. Balch; J. F. Balch; Prescription fro Nutritional healing, 3rd Edition.
  • Sharon R, Kathryn P, Ellie W.; (2008).Understanding Normal and Clinical Nutrition.8th edition.USA: Yolanda cossio.
  •; May 2012
  • ; May 2012
  • ; May 2012

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