By Elizabeth Landau, CNN
August 3, 2010 1:39 p.m. EDT
Ethan Wily, center, is allergic to certain nuts. His parents, Preston and Jen, are concerned about their next child.
(CNN)
-- Two-year-old Ethan Wily had a cold recently, so at first it wasn't
surprising that he started coughing last week after eating some
pistachio gelato.
But he started coughing up mucus, and then
gasping for air. His parents gave him an antihistamine, but it didn't
stop the reaction. By the time the boy's parents brought him to their
local hospital, he could barely breathe.
"His face was really
swollen. He looked like an alien," said Ethan's father, Preston Wily of
Lehi, Utah. "We didn't have any idea an allergy could be so bad."
He said the child had shown only a somewhat mild reaction to peanuts before this.
It
seems like more and more children in the U.S. are developing food
allergies, and there's data to back that up. The number of kids with
food allergies went up 18 percent from 1997 to 2007, according to the
U.S. Centers for Disease Control and Prevention. About 3 million
children younger than 18 had a food or digestive allergy in 2007, the
CDC said.
Scientists are still trying to figure out why food
allergies seem to be on the rise, especially in industrialized countries
such as the United States. Are children not getting exposed to enough
bacteria? Should they eat common allergens such as nuts and shellfish at
an earlier age?
Video: Guarding against food allergies
A recent study in the Journal of Allergy
and Clinical Immunology found that visits to the emergency room at
Children's Hospital Boston for allergic reactions more than doubled from
2001 to 2006. Although this is just one hospital, the findings reflect a
rise in food allergies seen in national reports, said Dr. Susan
Rudders, lead author and pediatric allergist-immunologist in Providence,
Rhode Island.
Researchers took a look at thousands of cases in
the emergency department. They did not rely on the diagnosis given at
that time, but made their own determination about whether an allergic
reaction had occurred based on symptoms such as hives. That means the
rise in reactions probably did not have to do with an increased
awareness among doctors, Rudders said.
This also suggests that
previous reported numbers of allergy-related hospital visits are
underestimates, Rudders said. For all adults and children in the U.S.,
there are 30,000 ER visits because of food allergies each year. But that
is based on a report that is about 10 years old, and this figure is
likely higher now, Rudders said.
Doctors in other parts of the
country have also noticed an increase in children coming in with severe
food allergies. Dr. Ronald Ferdman at the
Children's Hospital of Los Angeles said his hospital has seen a rise of these cases, based on anecdotal evidence.
Dr.
Joseph Zorc at the Children's Hospital at Philadelphia cautioned that
there may have been situational factors that influenced the Boston
hospital's experience -- for example, if another hospital in the area
stopped taking cases, resulting in more people at
Children's Hospital Boston. But he agreed that food allergies are causing more significant reactions in U.S. emergency departments in general.
One theory is that the Western diet has made people more susceptible to developing allergies and other illnesses.
A
study in Proceedings of the National Academy of Sciences compared the
gut bacteria from 15 children in Florence, Italy, with gut bacteria in
14 children in a rural African village in Burkina Faso. They found that
the variety of flora in these two groups was substantially different.
The
children in the African village live in a community that produces its
own food. The study authors say this is closer to how humans ate 10,000
years ago. Their diet is mostly vegetarian. By contrast, the local diet
of European children contains more sugar, animal fat and calorie-dense
foods. The study authors posit that these factors result in less
biodiversity in the organisms found inside the gut of European children.
The decrease in richness of gut bacteria in Westerners may have
something to do with the rise in allergies in industrialized countries,
said Dr. Paolo Lionetti of the department of pediatrics at Meyer
Children Hospital at the University of Florence. Sanitation measures and
vaccines in the West may have controlled infectious disease, but they
decreased exposure to a variety of bacteria may have opened the door to
these other ailments.
"In a place where you can die [from]
infectious diseases, but you don't get allergy, obesity, asthma,
inflammatory bowel disease, autoimmune disease, the flora is different,"
Lionetti said.
This study only looked at a small number of
children, but the findings support the widespread notion of the "hygiene
hypothesis" -- the idea that cases of allergies are increasing in
number and severity because children grow up in environments that are
simply too clean.
"That our immune system is skewed away from
fighting infections, and toward fight things that it's not supposed to
be fighting, like things in the environment or foods -- that's one thing
that people think may be in play," Rudders said.
Still, this is only speculation.
Another theory
is
that children need to get exposed to common allergens, such as nuts and
shellfish, from a much earlier age, to avoid developing allergies. Some
doctors have been recommending waiting until 2 or 3, but Ferdman at
Children's Hospital Los Angeles is a proponent of giving kids nuts very
early.
An oft-cited 2008 study in the Journal of Allergy and
Clinical Immunology compared peanut allergies among Jewish children
living in Israel and the United Kingdom. Peanut allergies were more
common among the children in the U.K. than in Israel. This was
associated with the fact that 69 percent of the Israeli children
received peanuts by 9 months of age, compared with 10 percent of the
infants in the U.K.
This pitfall, however, is that it was not a
controlled experiment, and other factors may have influenced the
allergies. More research needs to be done to support giving peanuts and
other common allergens to infants. But according to Ferdman, more
doctors are questioning recommendations to delay these foods.
These
issues about when to introduce allergens are crucial for Preston Wily
and his wife, Jen, who are expecting a second child next month. The
parents are planning to wait on introducing nuts until their daughter is
old enough to get tested for allergens, Preston said.
But hearing about recent research does make the father wonder whether delaying nuts could have influenced Ethan's allergies.
The
boy isn't the only one in his peer group with allergies. Ethan goes to a
nursery program at church where there's a wall of children's photos
with each kid's personal list of food allergies. The teacher has been
trained in how to use an epinephrine auto-injector in case of emergency.
Ethan's father knows now to administer an epinephrine injection as soon as the child begins to have a sign of anaphylaxis.
"There are a lot of kids here with allergies -- everywhere. It just seems more common now than when I was little," Wily said.
