Gerald Hurowitz, M.D.·Published 12 September 2012·8 min read
Key points
The number of children with peanut allergies in one Midwestern county has tripled in the past decade, according to a new study that adds to evidence nut allergies are getting more common in the developed world.
An allergic reaction occurs when your immune system overreacts and releases chemicals, including histamine, into your blood.
Symptoms of peanut allergy can range from mild to life-threatening.
Residents of Olmsted County from January 1, 1999, through December 31, 2007, who received medical care at a Rochester Epidemiology Project facility and provided research authorization were eligible for the study.
The number of children with peanut allergies in one Midwestern county has tripled in the past decade, according to a new study that adds to evidence nut allergies are getting more common in the developed world.
Researchers reviewed the medical records of several hundred children in Olmsted County, in southeastern Minnesota, and found that new diagnoses of peanut allergy rose from two out of every 10,000 kids in 1999 to nearly seven out of every 10,000 in 2007.
Overall, 65 of every 10,000 children in the county - home to a sophisticated countywide electronic health records system that provided data for the study - had a verified peanut allergy in 2007.
Though exact percentages of kids with peanut allergies may vary from place to place and study to study, Dr. Ruchi Gupta, an associate professor of pediatrics at Northwestern University's Feinberg School of Medicine in Chicago, who was not involved in the research, said, "What's consistent with this article is it does look like peanut allergies, especially among the younger children, are increasing over time."
Most, though not all, studies trying to gauge how widespread food allergies are among kids have tracked an increase in recent decades.
Food allergies are thought to affect eight percent of U.S. kids, with the most common culprits being cow's milk, wheat, egg, soy, peanuts, tree nuts and some seafood.
Peanut allergies typically appear early in life, when toddlers are first encountering solid foods, and about 20 percent of cases go away on their own as a child gets older.
Peanut Allergy StatisticsReliable peanut allergy statistics are not that easy to come by. There is a lot of available research on food allergies in general but not too many studies have been done on peanut allergy alone.
The internet is littered with hair-raising numbers about peanut allergy and other nut allergies but close examination may reveal that these peanut allergy statistics have been extrapolated or taken from studies with non-representative sample sizes.
Whether you think that prevalent peanut allergy statistics overstate or understate the problem, the important things to remember are: - Peanut allergy is a very real problem with a potentially fatal reaction - Someone who suffers a peanut allergy reaction should seek immediate medical attention - Epinephrine (adrenaline) is the only available treatment for a severe peanut allergy reaction - There are many nut-free foods and resources available to those with a peanut or other nut allergy
Here are a few related peanut allergy statistics accompanied by links to their sources. We encourage you to follow the links for a better understanding of the problem.
Written and revised by
Gerald Hurowitz, M.D.
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health.am provides general information, not medical advice. Always consult a qualified health professional about your own health.
Peanut allergy is one of the "Big 8" food allergies that account for 90% of those suffered by 21 million Americans. (AAAAI and FAAN)
More than 3 million people in the United States report being allergic to peanuts, tree nuts or both. (AAAAI)
Approximately 1% of the U.S. population has a peanut allergy (Sicherer, SH, "Prevalence of peanut and tree nut allergy in the US...")
Less than 21% of patients with peanut allergy will outgrow it. (AAAAI)
Peanut Allergy is the most common cause of food related death (AAFA).
Four out of every 100 children have a food allergy. (CDC/NCHS Study, "Food Allergy Among U.S. Children...")
From 1997 to 2007, the prevalence of reported food allergy increased 18% among children under age 18 years. (CDC/NCHS Study, "Food Allergy Among U.S. Children...")
From 2004 to 2006, there were an average of 9,537 hospital discharges per year with a diagnosis related to food allergy among children 0 to 17 years. (CDC/NCHS Study, "Food Allergy Among U.S. Children...")
Maria Rinaldi, lead author of the new report and an epidemiologist at the University of Minnesota in Minneapolis, said estimates of peanut allergy vary because of the way peanut allergy is defined for the purposes of research studies.
Some rely on parents' reports of allergy, which may or may not be validated by a doctor.
Rinaldi and her colleagues took a conservative approach, gathering data from the medical records of more than 500 Olmsted County children with suspected peanut allergies between1999 and 2007.
Rinaldi said her team, who published their findings in The Journal of Allergy and Clinical Immunology, used a strict definition of allergy, and only included children who had laboratory-confirmed peanut allergy, narrowing the group down to 171 kids.
They found that fewer children had been diagnosed with peanut allergy in 1999 compared to later years.
For instance, just 10 children in the county were diagnosed in 1999, and 30 were diagnosed in 2007.
"No matter how we're defining peanut allergy, we're seeing this consistent increase," Rinaldi told Reuters Health.
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Over three quarters of new diagnoses were in children under two years old, and about 70 percent were boys.
It's not clear why the food allergy has become more common.
"The leading theory is about hygiene - with less infection thanks to city living, smaller families, vaccines, sanitation, antibiotics, etc., the immune system is less 'busy' with germs and may become more prone to attack harmless food proteins," said Dr. Scott Sicherer, a pediatrics professor at Mount Sinai School of Medicine in New York, in an email.
Sicherer, who did not participate in the latest research, said another theory is that kids receive less vitamin D from sunlight because they are indoors or use sunscreen, and that could alter their immune system responses.
But these remain theories, and no one has proven why allergies are increasing.
Because peanut reactions can be severe, even lethal, measures to protect allergy sufferers from accidental exposure are becoming more common too, with peanut bans on airplanes, peanut-free sections of baseball stadiums and "school safe" packaged snacks manufactured in nut-free environments.
Gupta said it's important for parents to be aware of the potential signs of a food allergy, including hives, respiratory symptoms and digestion problems.
What is a peanut allergy? A peanut allergy is a reaction that occurs when your body mistakenly identifies peanuts as harmful substances. When you eat peanuts or food containing peanuts, your immune system-the body's natural defense system that fights infections and diseases-overreacts and can cause a serious, even life-threatening response.
What causes a peanut allergy?
An allergic reaction occurs when your immune system overreacts and releases chemicals, including histamine, into your blood. These chemicals can affect different tissues in the body, such as the skin, eyes, nose, airways, intestinal tract, lungs, and blood vessels. It's not clear why peanuts trigger this response in some people.
What are the symptoms?
Symptoms of peanut allergy can range from mild to life-threatening. If you have a mild reaction, you may get a stomachache, a runny nose, an itchy skin rash, hives, or tingling in your lips or tongue. If your reaction is worse, you may develop additional symptoms such as a tight throat, hoarse voice, wheezing, coughing, feeling sick to your stomach, vomiting, belly pain, and diarrhea. Your symptoms may start from within a few minutes to a few hours after eating peanuts or peanut products.
People who are allergic to peanuts may have a life-threatening reaction called anaphylaxis. Symptoms of anaphylaxis can include problems breathing and swallowing, vomiting and diarrhea, dizziness, dangerously low blood pressure, swelling of the lips, tongue, throat, and other parts of the body, and loss of consciousness. If not treated, death can result. Anaphylaxis usually occurs within minutes but can occur up to several hours after eating peanuts or peanut products.
She also urges parents to see a doctor if they suspect their child has an allergy.
People with peanut allergy should know about foods to avoid, as many who are allergic to peanuts are allergic to other nuts like walnuts, cashews or brazil nuts.
Doctors admit that the ubiquity of foods to avoid makes avoidance difficult and accidental ingestion common. Many of these foods are also popular with children, making it difficult to prevent contact or consumption. Good substitutes are available, however, for foods such as peanut butter.
Be sure to avoid foods that contain any of the following ingredients:
Peanut allergy diagnoses among children residing in Olmsted County, Minnesota
Methods
Residents of Olmsted County from January 1, 1999, through December 31, 2007, who received medical care at a Rochester Epidemiology Project facility and provided research authorization were eligible for the study. A medical chart review of 547 potential diagnoses resulted in 244 prevalent and 170 incident cases. Annual rates, crude and adjusted for age and sex, were standardized with the use of the indirect method to the Olmsted County population data in 1999. Incidence rate ratios were estimated with Poisson regression.
Results
The prevalence in 2007 was 0.65%. Female children were less likely to be diagnosed than male children (incidence rate ratio = 0.18; 95% CI, 0.07-0.48). Children aged birth to 2 years were significantly more likely to be diagnosed than older children aged 3-17 years (incidence rate ratio = 0.001; 95% CI, 0.0004-0.004). A significant 3-fold increasing trend was observed in diagnoses over time from 2.05 cases per 10,000 children in 1999 to 6.88 cases per 10,000 in 2007.
Conclusions
Peanut allergies are an increasing concern in Olmsted County, Minnesota, as indicated by a 3-fold increase in diagnoses from 2.05 per 10,000 children in 1999 to 6.88 per 10,000 children in 2007.
Maria Rinaldi, Lisa Harnack, Charles Oberg, Pamela Schreiner, Jennifer St. Sauver, Lori L. Travis The Journal of Allergy and Clinical Immunology - 03 September 2012 (10.1016/j.jaci.2012.07.042)
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