HEALTH

Each year, approximately 50 million Americans suffer from allergies—but really, “people use the word allergy to describe anything they just don’t like.” (Popular Science)

Lactose intolerance is not an allergy, for example.

Teachers, scroll down for a quick list of key resources in our Teachers Toolkit.

Discussion Ideas

• Today, allergies are typically defined by the presence of immunoglobulin E, or IgE, antibodies. What are IgE antibodies?
  • Antibodies are large, y-shaped proteins used by the immune system to fight pathogens. Each tip of a specific antibody is targeted to a specific antigen, the molecule of a pathogen.
  • Immunoglobulin E (IgE) is an antibody that mostly targets pathogens like intestinal worms and the organisms that cause malaria. So, good to have.
  • IgE also plays a role in the development of histamines. Histamines are chemical compounds that are part of a body’s standard response to foreign pathogens. The symptoms associated with allergies—watery eyes, itches, sneezes—are just reactions to expel pathogens from your body. Allergies are histamines “overreacting” to some antigens.
    • Take a look at the nice infographic above:
      • A person encounters an allergen (antigen) such as the chemicals in ragweed.
      • The person produces large amounts of the IgE antibody targeted at ragweed.
      • The IgE antibodies attach themselves to mast cells (white blood cells).
      • The person again encounters the ragweed allergen.
      • The white blood cells release histamines.
      • Histamines cause symptoms of an allergy—sneezing, irritated eyes, runny nose, etc.—to rid the body of ragweed antigen.

• The Popular Science article claims many symptoms people are calling allergies are not actually allergies. So what is an allergy?
  • What Popular Science calls a “legitimate allergy” is the result of an aggressive immune system response (histamines) to a fairly common compound (allergen).

• What are some examples of “legitimate allergies”?
  • “hay fever” (allergic rhinitis) associated with pollen, dust, pet dander, and mold. Allergies associated with these compounds are usually concentrated in areas that directly encounter the allergen—your eyes (watery), your nose (runny or sneezing), your skin (rashes), and your mouth and throat (coughing).
  • food allergies. Food allergies are usually more aggressive than hay fever allergies. They can involve more serious rashes, intestinal illnesses, and, at worst, anaphylaxis. Anaphylaxis is a severe reaction that may include low blood pressure, constriction of your airways due to a swollen throat and tongue, fainting, vomiting or diarrhea, and, if severe and untreated, death.
    • Symptoms of food allergies usually appear suddenly, consistently, and can be triggered by even a small amount of the food allergen.
    • According to WebMD, eight food groups cause about 90% of food allergies:
      • milk
      • eggs
      • peanuts
      • tree nuts
      • soy
      • wheat
      • fish
      • shellfish

• What are some examples of “not-an-allergy”?
  • food intolerances. Symptoms of food intolerances are usually less severe than food allergies. Symptoms of food intolerances appear much slower than allergic reactions, are often dependent on the consumption of larger or more frequent amounts of the food, and usually include an upset stomach.
    • So, lactose intolerance is not an allergic reaction to milk. Lactose tolerance is, actually, a genetic mutation. Learn about that fascinating evolutionary process here.
  • autoimmune disorders. “Celiac disease, which causes a severe reaction to gluten, affects approximately 1% of Americans. But it’s not an IgE-mediated food allergy; it’s an autoimmune disorder … For people with celiac, ingesting gluten causes the body to attack its small intestine, preventing proper nutritional absorption.”

• Antihistamines are drugs that reduce the natural biological response of some histamines. Can antihistamines like Benadryl treat food intolerances or celiac disease?
  • No. Food intolerances and autoimmune diseases are not the result of aggressive histamines. Benadryl won’t help, but diet and your doctor can.

TEACHERS TOOLKIT

Popular Science: You’re almost certainly using the word ‘allergies’ wrong

Nat Geo: Talking Evolution: Are We Still Evolving?

Medline Plus: Allergic rhinitis

WebMD: Food Allergy or Intolerance?

Mayo Clinic: Celiac disease