Allergies:What are they, why do we have them, and why do they seem

more common today?

By: Gabrielle Mendes

Which baby do you think is more likely to develop allergies?

Baby from the United States

Baby from Namibia

True or False?

1 in 10 Americans have symptoms of

allergies or asthma

False- 1 in 5 Americans have

symptoms of allergies or asthma

The likelihood of having allergies is

determined solely by one's genetics

True or False?

False

Allergies can be cured

True or False

False

Survey results• Not many people knew how allergies

are acquired:o "They lack the ability to deal with certain

things"o "It's a reaction to the increase in pollen"o "Some people lack immunity to certain

everyday things like food or plants"

• 11% of people said they knew nothing about allergies; 26% said they knew only a little bit about allergies; 37% said they knew some information about allergies; 26% said they knew a lot about allergies

Survey Results Continued• 79% of people had allergies• the most popular allergens were

pollen, cat fur, and ragweed• other allergens included amoxicillin,

finned fish, mold, penicillin, oak trees, mold, dust mites, lactose, and dog fur

• two people had deadly allergies - one to anti inflammatory drugs - the other to Penicillin, Augmentin, and Ampicillin

• Allergies are abnormal reactions of the immune system that occur in response to otherwise harmless substances (From The Medical Dictionary online)

What is an allergy?

• dust mites• pollen• mold• animal dander• insect stings• latex• food

-milk-eggs-peanuts-tree nuts (like almonds, cashews)-fish-shellfish-soy-wheat

• medication Penicillin

Common symptoms• sneezing• itchy eyes/ throat/ nose• nasal congestion• coughing• itchy mouth/ throat• hives• rash• abdominal cramps• nausea• vomiting• diarrhea • difficulty breathing• shock• throat swelling• hives• difficulty breathing• shock• nausea• diarrhea

airborne allergies

food allergies

insect venom allergies

How does this work?

• When exposed to an allergen:o immune system will

produce immunoglobulin antibodies for the allergen

o these antibodies will cause body cells to produce histamines (a chemical)

o histamines will affect different parts of the body like the nose, eyes, throat, and lungs

Genetics:-In a study done by the Department of

Biological Psychology at Vrije Universiteit in Amsterdam, 3600 5-year-old twins were studied:

-50-80% of the time, identical twins shared allergies

-25-40% of the time, fraternal twins shared allergies

How are allergies acquired?

Genetics continued• Atopy: the genetic predisposition to

develop allergies or allergic diseases (www.neocate.com)o studies have shown that if one parent is

atopic, about 30% of their children will have allergies

o if both parents are atopic, about 50% will have allergies

o the inheritance of allergies does not follow the traditional Mendelian inheritance pattern caused by the interactions of many genes

and environmental triggers heredity may cause you to have a type of

allergy, not a specific allergy

• industrialized nations have more people with allergies than developing or agrarian nationso Hygiene Hypothesis

clean environment = weaker immune system• "Kids need to play in the dirt"

Environmental Factors

Environmental Factors continued• Global warming:

o spring arrives 10 to 14 days earlier than it used to, making spring allergies worse

o ragweed grows well under increased carbon dioxide levels - ragweed plants today are able to produce twice as much pollen as they did 100 years ago

• 80% of children will grow out of their milk, eggs, wheat, and soy allergies by adulthood, (according to Dr. Robert Wood from Johns Hopkins Children's Center)

• 20% of children grow out of their peanut allergy• 10% will grow out of their tree nut allergy• usually children grow out of their allergies around

puberty

• Professor Katie Allen in the Department of Allergy and Immunology at the Royal Children's Hospital in Melbourne did a study to see if children would grow out of an allergy:o "If your child came to me at 12 months of age [and I did a

skin prick test] and I then redid the skin prick test at two, three and four and if I found the skin prick test went from 10 mm, 8mm, 6 mm to 2mm then I would be able to reliably tell you that your child has a good chance of growing out of peanut allergies," says Allen.

Why do children grow out of allergies?

• Allergy rates have doubled since the 1970s

• From 1997 to 2007, the number of children with food allergies rose 18 percent

• Possible Factors:o Global warming

o Hygiene Hypothesis

o Increased knowledge/diagnosis of allergies

Are allergies more common today?

• No, but there are ways to treat allergies:o Immunotherapy: "allergy shots" - alleviate

the symptoms of allergieso Medication

Antihistamines stop allergy symptoms (Allegra, Benadryl, Zyrtec)

Anti-inflammatory drugs reduce inflammation (Deltasone, Rhinalar)

Can an allergy be cured?

Works Cited"ABC Health & Wellbeing." Allergies. N.p., n.d. Web. 10 June 2013.

"Allergies and Global Warming." - National Wildlife Federation. N.p., n.d. Web. 10 June 2013.

Borish, L. "Result Filters." National Center for Biotechnology Information. U.S. National Library of Medicine, n.d. Web. 10 June 2013.

Deardorff, Julie. "Children Can Grow out of Allergies." The Montana Standard. Montana Standard, 19 Apr. 2011. Web. 10 June 2013.

"KidsHealth." All About Allergies. Kid's Health, n.d. Web. 10 June 2013.

West, Mallory. "Allergies and Genetics." Nutricia Neocate. Neocate, n.d. Web. 10 June 2013.

http://serendip.brynmawr.edu/biology/b103/f03/web3/m1teicher.htmlhttp://www.webmd.com/allergies/guide/allergy-shots?page=2