Understanding Allergies

  1. What is an Allergy?
    1. An allergy is an acquired sensitivity of the immune system. This means that the body’s immune system has become sensitive to one or more common, harmless substances in our environment, such as pollen, dust, molds or even food.  This sensitivity causes an immune response which results in symptoms that range from mild (runny nose, watery eyes, sneezing and itching) or severe (hives, trouble breathing or anaphylactic shock).  Symptoms usually occur with each exposure to the allergen.
  2. Allergens
    1. An allergen is a general term used to describe something that causes an allergic reaction. Allergens are actually tiny proteins found on certain substances.  Some examples are airborne allergens, like pollen and mold; foods like shellfish, peanuts and milk.  Venom from an insect sting contains allergens as do plants, like poison ivy.  Allergens also exist in households, like dust mites.  Only those who are prone to acquired sensitivity are regularly affected by these allergens. 
  3. Pathway of an Allergic Reaction.
    1. Two phases exist in allergic reactions, primary exposure and re-exposure. In this example the primary exposure is from allergens in the venom of an insect sting.  (picture – wasp)
  4. Anaphylaxis: An Allergic Emergency.
    1. Anaphylaxis is a life-threatening reaction. The onset of this reaction occurs within seconds or minutes of exposure.  Symptoms include red raised blotches over most of the body, skin becomes warm to the touch, intense tightening and swelling of the airways makes breathing difficult, and there is a drop in blood pressure.  Breathing can stop and the body may slip into shock.  If medication is not quickly administered, heart failure and death can result within minutes.  Allergens in insect venom and injectable medications are more likely to cause anaphylaxis than any other allergen.  Anaphylaxis is not a common reaction and can be controlled with prompt medication and the help of a physician.
  5. Who Gets Allergies?
    1. The tendency to develop allergies is thought to be inherited, because they commonly develop in those who have a family history. However, it is possible for anyone to develop allergies at any age.  Environmental factors can make our immune systems overly sensitive.  This could then trigger allergies in people with no family history or help its onset in those that have a family history.
  6. Household Allergies.
    1. Dust mites are microscopic organisms that live on human skin scales which we shed off regularly. They are commonly found on pillows, mattresses, upholstered furniture and in clothes changing areas.  This organism is responsible for most of the year-round type allergic rhinitis. 
  7. Insect Allergies
    1. The venom that is injected by wasps and bees contains allergens which can cause an allergic reaction in 1 out of 10 people. Those not allergic to insect stings or bites probably experience normal swelling & skin irritation that lasts for a few hours.  Those with insect allergies tend to have large areas of hives, swelling and itching that may last for days or weeks.  However, for others, the reaction can develop into a life-threatening emergency called anaphylactic shock.  Anyone with a sensitivity to insect stings or bits should see an allergist for diagnosis and treatment.
  8. Asthma
    1. Asthma is a condition in which there is tightening, swelling and increased mucus secretion of the airways in the lungs. This causes difficulty breathing, wheezing and tightening of the chest.  It is most common in children and can be mild or a life-threatening reaction.  This condition can be caused by inhaling allergens such as pollen, pet dander, and dust; however, not all asthma is related to allergies   It can also be triggered by irritants such as tobacco smoke.
  9. Food Allergies
    1. Allergies to foods can cause swelling of the lips, throat, face and tongue; cause an upset stomach, vomiting, cramps, hives, eczema and even asthma. Some common food allergens are milk, soy, eggs, peanuts, wheat, fish and shellfish.  Food allergies are most common in childhood, but can also occur in adults.
  10. Skin Allergies
    1. Skin covers the entire body protecting us from the environment we live in. Skin is exposed daily to a variety of allergens.  Skin is especially sensitive to allergens, because of the large number of mast cells and T-cells found in its tissues.  Allergies of the sink are very common.  Symptoms can include: swelling, hives, itching and redness of the skin.  Common skin allergies called “contact dermatitis” are caused by plants, such as poison ivy, poison oak and poison sumac.  Also included are certain detergents, creams and jewelry.  Hives may be caused by some drugs and foods.
Laura Rogers Allergy & Asthma MD