BITES
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By Dr Soh Jian Yi
The Truth About Food Allergies
Food allergies are a
common problem, and
a common concern, to
parents and doctors
worldwide. Singapore is no
exception to this rule. In
our society, what is known
about food allergy is often
passed down through
word of mouth, and more
recently, the Internet has
become another source of
information.
Unfortunately, this information – some
true, some false – can prove to be
confusing. The beliefs differ from family
to family and from website to website, and
can at times contradict each other.
Here are answers to some of the
common questions that parents have
about food allergy:
Q
Which are the foods children are
often allergic to? When do these
allergies appear?
Parents of children with food allergy will
notice two main patterns depending on the
age of their child:
1 For young children, usually infants
(babies less than a year old): aside from
breastmilk, infant formula (cow’s milk)
is often the first food that babies are
exposed to. Egg is another common food
that babies will be fed. Consequently,
those who have allergy to cow’s milk and
eggs, will be noticed at this age.
2 For older children above 5 years of age:
allergy to shellfish – prawns, crabs,
lobsters, mussels, oysters, and so on – is
the most common issue among older
children, as well as adults. Older children
may also develop allergy to other foods,
the more commonly-seen types being
peanuts, tree nuts, wheat, soy, and fish.
Q
My child had a rash. I think it might be
due to a food allergy. What should I do?
Parents often first become concerned
over a rash after the child eats something.
However, rashes can be due to many
reasons, and the most common causes
of rash in children are those related to
infections and “heat rash”, rather than food
or drugs.
If you suspect your child has a food allergy,
do consult with your paediatrician or a
paediatrician who specialises in allergy. It
is important for your doctor to diagnose
whether a child truly has a food allergy or
not, as this has implications for the child’s
long-term diet.
Q
If I think my child has a food allergy,
shouldn’t I just avoid the food? Do I
really need to see a doctor?
The first abovementioned implication is
on the child’s diet. Some of the ingredients
your child might be allergic to are found in
different food products. A child with true
food allergy can be accidentally exposed
to the same food again, resulting in future
reactions that can be more severe, or even
life-threatening. Here, your doctor can
appropriately advise you on what foods
your child cannot take, so as to avoid this
problem. Your doctor can also teach you
about what to do if your child develops
an allergic reaction, and may prescribe
medication for such an event.
If the food ingredient is a common one in a
regular diet, your doctor can also advise you
on reasonable alternatives to ensure your
child’s nutrition, growth and development
is not compromised. For example, in
children with cow’s milk allergy, cases of
malnourished children due to excessively
restricted diets have been reported. To
make matters more complicated, many
children “outgrow” certain food allergies,
such as cow’s milk and hen’s eggs. Finding
out when this happens and being able to
allow the child to safely take those foods
again, is something that your child’s doctor
can do.
Conversely, a child without food allergy
may be unnecessarily forced to avoid
certain foods because of the parents’ beliefs.
An example would be in a child with
suspected cow’s milk allergy. Cow’s milk is
a common ingredient in dairy products. If
the child does not have cow’s milk allergy
but the parents think he/she does, they may
have their child unnecessarily avoid all milk
and dairy products, which are important
sources of nutrition to the growing child.
The second implication is the stress and
anxiety that parents and children face
when they do not know (or mistakenly
believe) if a child has food allergy. This
means checking the ingredient lists on
processed foods bought at the supermarket,
food prepared at the childcare centre,
kindergarten, school canteens, overnight
camping trips, school outings, family
reunions, and so on. There is enough
stress in everyone’s daily life, such that this
burden should not be unnecessarily added
on to anyone, child or parent.
Q
Can food allergies actually be
prevented or avoided?
There is no obvious way to do this.
It was previously thought that pregnant
mothers eating certain “allergenic”
foods, like cow’s milk and eggs, or early
introduction of these foods into the
baby’s diet, increased the risk of a child
developing an allergy. This led to varying
practices among parents – with some
delaying, for instance, the introduction
of egg until well after the age of 1 year;
and others completely avoiding nuts
and shellfish for years – it had also
influenced the feeding guidelines of wellknown organizations, such as that of the
American Academy of Pediatrics (AAP).
In 2000, the AAP’s feeding guidelines
recommended that breastfeeding mothers
of infants at high risk for developing
allergy should avoid cow’s milk, egg, fish,
peanuts and tree nuts. Parents were also
instructed that solid foods should not
be introduced into the diet of high-risk
infants until 6 months of age, with delay
in the introduction of dairy products,
eggs, peanuts, nuts and fish.
In 2008, the AAP reversed its stand in its
feeding guidelines. This is because there
is no evidence showing that having a
pregnant mother avoid certain foods, or
delaying the introduction of solid food
beyond 4 - 6 months of the infant’s age,
actually prevented the development of
food allergy. There is some evidence to
suggest that deliberately avoiding foods
may, in fact, increase the risk of allergy.
Q
If the child’s parents, brothers or sisters
have food allergy, how likely is it that
the child will have a food allergy too?
The chance of “inheriting” a food allergy
is small. There is a genetic component
– that is, a risk due to the common
genes in the family – but it appears
that the environment plays a big role in
determining whether a person actually
gets a food allergy. Unfortunately, no one
yet knows for certain what it is in the
environment that determines this.
Q
My child is allergic to eggs. Can the
MMR vaccine be given safely to
him/her?
Yes. No extra precautions, such as taking
medications beforehand or delaying the
MMR vaccine, are needed in children with
an egg allergy.
Dr Soh Jian Yi
Associate Consultant
Division of Paediatric Allergy, Immunology and
Rheumatology, National University Hospital
42
Family & Life • Sept 2013