Facts of Life

Facts of Life:
Issue Briefing for Health Reporters
Vol. 12, No. 1
January 2007

The Rise of Childhood Allergies

The Issue

The Facts

Allergy Side Effects: Stress and Isolation

Expert Sources

References

The Issue:

Familiar headlines: another classroom becomes a peanut-free zone, another inner-city child rushes to the emergency room in the throes of a severe asthma attack. News coverage of childhood allergies is on the rise, but the trend reflects a true increase in the prevalence of allergy and asthma in the past decade.

Widespread and Growing

The International Study of Asthma and Allergies in Childhood has surveyed more than 700,000 children in 56 countries since 1991. The latest numbers from ISAAC show a significant worldwide increase in allergy symptoms, particularly among younger children.¹ "I think it is a pretty global increase, as we have seen the rise in various types of allergies -- food, pollen, animal dander, and in types of allergic disease -- asthma, allergic skin disease, hay fever and food allergies," says Scott Sicherer, M.D., a pediatric allergy specialist at Mount Sinai School of Medicine in New York.

Why Now?

The startling trend has researchers scrambling to find a cause that can explain both the speed and the scope of the rise in childhood allergy. One of the most popular explanations is the "hygiene hypothesis," which suggests the cleanliness of Western lifestyles has banished many of the infectious agents that train a child's immune system, making it prone to allergic overreaction. ²Other possible culprits include pollen increases from global warming³, environmental toxins⁴, common medications ⁵ and changes in diet.⁶

The Facts:

• A 2000 review of asthma trends worldwide concluded that asthma is more common in Western countries and that asthma prevalence increases in countries as they become more urban and westernized. ⁷
• Asthma prevalence among children in the United States rose from 3.6 percent in 1980 to 6.2 percent in 1996. ⁸
• A 2003 national telephone survey suggests the prevalence of children's peanut allergies doubled between 1997 and 2002. ⁹
• Cockroach and mouse allergens at levels high enough to contribute to asthma were found throughout a nationally representative sample of U.S. households, according to two recent studies. ^10,11
• In a study of nearly 14,000 7-year-old children in the United Kingdom, grass pollen and dust mites were the most common allergy triggers. ¹²
• Some evidence links obesity to a higher risk of developing asthma, but the underlying mechanism is not clear, finds a recent review. ¹³
• Firstborns may have a greater risk of developing asthma, allergy and eczema than later-born siblings, according to some studies. ^14,15
• A child's risk of developing a food allergy is greater when the child is fed solid foods before six months of age, according to a 2006 review.¹⁶
• Intestinal parasites do not offer protection against the development of asthma, according to a 2006 systematic review. ¹⁷
• Soy formula does not prevent food allergy among infants at risk for such allergies, while hydrolyzed milk formula (milk proteins broken into tiny digestible pieces) may prevent wheezing in infants with a family history of asthma, according to two systematic reviews.^18,19
• In a recent survey, 34 percent of parents who have children with food allergies said this has affected their child's school attendance. ²⁰
• In another survey, 54 percent of teenagers with a food allergy said they sometimes purposely ate their "trigger" food. ²¹

Allergy Side Effects: Stress and Isolation

For some children with food allergies, birthday parties, soccer games and school field trips are dreaded ordeals. Rather than face an unknown and uncontrolled food situation, families opt out. In a recent survey of 87 families, pediatric allergy specialist Mary Bollinger, D.O., and colleagues at the University of Maryland found that half had made significant changes to their social activities to accommodate their child's food allergy. ²⁰

Food allergies also affect home life, especially meal preparation. But Bollinger says allergies seem to have a greater impact on outside activities, "perhaps because there is a feeling of less control."

Scott Sicherer, M.D., a food allergy specialist, says that many families shy away from events with food, at least at first. "Sometimes it takes a lot of preparation to participate safely and so there could be reluctance. So many social activities are food-centric."

Parents may be more anxious at the thought of sleepover camp or an after-school snack than the children themselves. In Bollinger's study, 41 percent of the parents surveyed said their child's allergy had a "significant impact" on their own stress levels.

When Sicherer and colleagues asked a small group of teenagers and their parents about the worst part of having a food allergy, "the main parental answer was fear and anxiety about death in the event of a reaction. For the teens, the main problem was social issues."

" You can imagine a teen's wish to fit in rubs against some aspects of food allergy management" such as eating at a fast food restaurant, Sicherer says.

Sicherer's work "showed that the main thing teens wanted was for people around them to understand the allergy." Peer education "is an area of food allergy management that is sometimes overlooked," he says.

So far, there are very few studies about how stress and avoiding activities might affect the psychological and social development of children with allergies, Bollinger says. Her team is working on further studies to find out how food allergies might affect the relationship between parent and child.

The allergy itself can have potentially serious health consequences that should not be taken lightly, according to Bollinger: "If the child is going to be cared for by someone out of the home, it is important for them to understand the dietary restrictions and how to treat an allergic reaction."

Sicherer, who has written a book for parents of children with food allergies ²², says, "A balance can be obtained with a healthy amount of worry to be safe but not so much fear that social activities become problematic." He says that parents should know as much as they can about their child's allergies and how to deal with emergencies so that social situations will seem less overwhelming.

" People with a food allergy should do and can do everything that a person without food allergies does, except for eating the food to which they are allergic," Sicherer says.

Expert Sources:

References

1. M. I. Asher et al. (2006) Worldwide time trends in the prevalence of symptoms of asthma, allergic rhinoconjunctivitis, and eczema in childhood: ISAAC Phases One and Three repeat multicountry cross-sectional surveys. The Lancet, 368: 733-743.

2. D. Strachan (1989) Hay fever, hygiene, and household size. British Medical Journal, 299: 259–260.

3. P.J. Beggs and H.J. Bambrick (2005) Is the global rise of asthma an early impact of anthropogenic climate change? Environmental Health Perspectives, 113: 915-919.

4. M.K. Selgrade et al. (2006) Induction of asthma and the environment: what we know and need to know. Environmental Health Perspectives, 114: 615-619.

5. I. Eneli et al. (2005) Acetaminophen and the risk of asthma: the epidemiologic and pathophysiologic evidence. Chest, 127: 604-12.

6. F.S.F. Ram and K.D. Ardern (2004) Dietary salt reduction or exclusion for allergic asthma. The Cochrane Database of Systematic Reviews, Issue 1.

7. R. Beasley et al. (2000) Prevalence and etiology of asthma. Journal of Allergy and Clinical Immunology, 105: S466–472.

8.Centers for Disease Control and Prevention. “Asthma’s Impact on Children and Adolescents.” Last accessed 12-07-06 at http://www.cdc.gov/asthma/children.htm.

9. S.H. Sicherer et al. (2003) Prevalence of peanut and tree nut allergy in the United States determined by means of a random digit dial telephone survey: a 5-year follow-up study. Journal of Allergy and Clinical Immunology, 112: 1203-1207.

10. R.D. Cohn et al. (2004) National prevalence and exposure risk for mouse allergen in US households. The Journal of Allergy and Clinical Immunology, 113: 1167-1171.

11. R.D. Cohn et al. (2006) National prevalence and exposure risk for cockroach allergen in U.S. households. Environmental Health Perspectives, 114: 522-526.

12. G. Roberts et al. (2005) Relationship between aeroallergen and food allergen sensitization in childhood. Clinical and Experimental Allergy, 35: 933-940.

13. B. Schaub and E. von Mutius (2005) Obesity and asthma, what are the links? Current Opinion in Allergy and Clinical Immunology, 5: 185-193.

14. W. Karmaus et al. (2001) Does the sibling effect have its origin in utero? Investigating birth order, cord blood immunoglobulin E concentration, and allergic sensitization at age 4 years. American Journal of Epidemiology, 154: 909-915.

15. R.M. Bernsen et al. (2003) Birth order and sibship size as independent risk factors for asthma, allergy, and eczema. Pediatric Allergy and Immunology, 14: 464-469.

16. A. Fiocchi et al. (2006) Food allergy and the introduction of solid foods to infants: a consensus document. Adverse Reactions to Foods Committee, American College of Allergy, Asthma and Immunology. Annals of Allergy, Asthma and Immunology, 97: 10-20.

17. J. Leonardi-Bee et al. (2006) Asthma and current intestinal parasite infection: systematic review and meta-analysis. American Journal of Respiratory and Critical Care Medicine, 174: 514-523.

18. D.A. Osborn and J. Sinn (2006) Soy formula for prevention of allergy and food intolerance in infants. The Cochrane Database of Systematic Reviews, Issue 4.

19. F.S.F. Ram et al. (2001) Cow's milk protein avoidance and development of childhood wheeze in children with a family history of atopy. The Cochrane Database of Systematic Reviews, Issue 4.

20. M.E. Bollinger et al. (2006) The impact of food allergy on the daily activities of children and their families. Annals of Allergy, Asthma and Immunology, 96: 415-421.

21. M.A. Sampson et al. (2006) Risk-taking and coping strategies of adolescents and young adults with food allergy. Journal of Allergy and Clinical Immunology, 117: 1440-1445.

22. S. Sicherer (2006) Understanding and Managing Your Child's Food Allergies. Baltimore, MD: The Johns Hopkins University Press.

The Center for the Advancement of Health is an independent nonprofit organization that promotes greater recognition of how psychological, social, behavioral, economic and environmental factors influence health and illness. The Center advocates the highest quality research and communicates it to the medical community and the public. The fundamental aim of the Center is to translate into policy and practice the growing body of evidence that can lead to the improvement and maintenance of the health of individuals and the public. The Center was founded by the John D. and Catherine T. MacArthur Foundation and the Nathan Cummings Foundation, which continue to provide core funding. Funding for this series was provided by the Robert Wood Johnson Foundation.

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