THURSDAY, Aug. 22 (HealthDay News) -- Boys diagnosed with
attention-deficit/hyperactivity disorder are more likely also to
have asthma, allergies and skin infections than youngsters without
ADHD, a new study finds, suggesting a possible link between these
Of those in the study, boys newly diagnosed with ADHD were 40
percent more likely to have asthma, 50 percent more likely to have
needed a prescription for allergy medicine and 50 percent more
likely to have had a bacterial skin infection than other boys.
"Our study provides additional evidence to support the
hypothesis that atopic disorders, such as asthma and food allergies
increase the risk of developing ADHD," the authors wrote, adding
that further research is necessary to determine just how these
conditions might be connected.
Their results were published in the August issue of the
Annals of Allergy, Asthma & Immunology.
ADHD, a chronic mental health condition involving difficulty
paying attention, hyperactivity and impulsivity, affects as many as
9 percent of American children, according to background information
in the study conducted by Eelko Hak, of the University of
Groningen, and colleagues in the Netherlands and Boston.
The increase in the prevalence of ADHD has been paralleled by an
increase in allergic (also called atopic) diseases, such as asthma
and allergies, the researchers reported. They also noted that
environmental risk factors, such as foods that cause an allergic
reaction, may trigger symptoms of both ADHD and allergic
To get a better idea of whether or not there actually is an
association between these conditions, the researchers used data
from a large U.K. study. Within that database, the researchers
found nearly 900 boys who were first diagnosed with ADHD and
prescribed medication for the condition between 1996 and 2006. All
of the boys were between 4 and 14 years old when first
The researchers compared the children with ADHD to about 3,500
children without the condition.
After adjusting the data to account for age, and for low birth
weight or premature birth, they found significant relationships
between the diagnosis of ADHD and a history of asthma, impetigo or
a prescription for antihistamines (allergy medicines).
They also found weaker associations between ADHD and cow's milk
intolerance, and prescriptions for oral or topical corticosteroids,
antibacterial or antifungal drugs.
The authors theorize that the links they found may be
food-allergy related. However, this study didn't attempt to prove
cause and effect, so the exact reason behind the association
Dr. Andrew Adesman, chief of developmental and behavioral
pediatrics at Steven and Alexandra Cohen Children's Medical Center
of New York, said the connection between ADHD and allergic diseases
has been seen in other studies.
"The association seems to be real. The chicken-and-the-egg
question remains unanswered. The challenge is in teasing out why
they're linked," he said.
For her part, Dr. Jennifer Appleyard, chief of allergy and
immunology at St. John Hospital and Medical Center in Detroit,
said, "This is an interesting, but very early study. They're
definitely not showing cause and effect."
Appleyard pointed out that impetigo and milk intolerance aren't
typically considered allergic diseases. Impetigo is a bacterial
infection of the skin. And, a milk intolerance isn't the same as an
allergy to milk.
"They looked at food allergies, too, and they didn't find an
association. They also didn't find an association with atopic
dermatitis [eczema], and impetigo is not necessarily correlated
with an allergic reaction," she said.
The bottom line, she said, is that parents don't need to have
any additional fears from this study. She added that parents of
children with asthma or allergies shouldn't start worrying that
their children will develop ADHD -- and parents definitely
shouldn't make any changes to medications because of this
"All of these conditions seem to have increased. Let's pursue
this link further, but there's no need for any changes right now,"
Learn more about attention-deficit hyperactivity disorder from
U.S. National Institute of Mental Health.