There
is much in the media about food allergies and intolerance's, but what is the
difference? And can you tell fact from fiction?
Food intolerance
A food
intolerance is not the same as a food allergy.
People
with a food intolerance may have digestive symptoms such as diarrhoea,
bloating and stomach cramps.
This
may be caused by difficulties digesting certain substances, such as lactose.
However, no allergic reaction takes place.
Important
differences between a food allergy and food intolerance include:
• The
symptoms of a food intolerance usually only occur several hours after eating
the food.
• You
need to eat a larger amount of food to trigger an intolerance than an allergy.
• Unlike
an allergy, a food intolerance is never life-threatening.
Oral allergy syndrome
A
relatively common type of food allergy in adults is known as oral allergy
syndrome.
This
type of food allergy causes itching, tingling and swelling of the mouth, lips
and /or throat.
Oral
allergy syndrome is most commonly triggered by fresh fruit, vegetables and nuts.
Five facts about allergies
Around
one person in four in Britain suffers from an allergy, and it’s got worse in
the last 10 years.
A food
allergy is when the body's immune system reacts abnormally to specific foods.
Allergic reactions are often mild, but they can sometimes be very serious.
Allergic reactions are often mild, but they can sometimes be very serious.
In
children, common food allergies include being allergic to milk and
eggs. In adults, allergies to fruits and vegetables are more common. Nut
allergies, such as being allergic to peanut, are relatively common in both
children and adults.
Symptoms
of a food allergy can affect different areas of the body at the same time. Some
common symptoms include:
• an
itchy sensation inside the mouth, throat or ears
• raised
itchy red skin rash (this is known as urticaria, hives or "nettle
rash")
• swelling
of the face, around the eyes, lips, tongue and the roof of the mouth (this is
known as angioedema)
Anaphylaxis
In the
most serious cases, a person has a severe allergic reaction (anaphylaxis),
which can be life-threatening.
If you
suspect that somebody is experiencing the symptoms of anaphylaxis, such as
breathing difficulties and swollen lips, immediately call 999 for an
ambulance and tell the operator that you think the person has anaphylaxis.
What causes food allergies?
Food
allergies are caused when the immune system (the body’s defence against
infection) mistakenly treats proteins found in food as a threat to the body,
when in fact they should be harmless.
It then
releases a number of chemicals to prevent what it sees as an infection taking
hold. It is these chemicals that cause the symptoms of an allergic reaction.
Any
food could cause an allergic reaction, but there are certain foods that are
responsible for most food allergies.
In
children, the foods that most commonly cause an allergic reaction are:
• milk
• eggs
• peanuts
• tree
nuts
• fish
• shellfish
The
majority of children with a food allergy have a background of eczema (an
allergic skin condition) during infancy. The worse their eczema is and the
earlier it started, the more likely they are to have a food allergy.
In
adults, the foods that most commonly cause an allergic reaction are:
• some
types of fruit such as apples, pears, kiwi fruit and peaches
• some
types of vegetables such as potatoes, carrots, celery and parsnip
• crustaceans
(shellfish), such as crab, lobster and prawns
• tree
nuts, such as walnuts, brazil nuts, almonds and pistachios
• peanuts
• fish
It is
still uncertain why people develop allergies to food, although often people
with a food allergy have other allergic conditions such as asthma, hay fever
and eczema.
Types of food allergies
The
most common type of food allergy is triggered by an antibody called
immunoglobulin E. This is known as IgE-mediated food allergy and tends to cause
rapid symptoms, often within seconds or minutes of exposure to certain foods.
There is a greater risk of anaphylaxis with this type of allergy.
Allergic
reactions not caused by immunoglobulin E (non IgE mediated food allergy) tend
to cause symptoms hours or even days after exposure to certain foods. This
type of allergy is often difficult to diagnose.
Treatment
There
is no treatment to cure a food allergy. The best way of preventing an allergic
reaction is to identify the type of food that causes the allergy and then avoid
it in future.
However,
avoid making any radical changes to your child’s diet, such as cutting dairy
products, without first consulting with your GP.
A type
of medication called an antihistamine can help relieve the symptoms
of a mild to moderate allergic reaction. A type of medication called adrenaline
is an effective treatment for anaphylaxis.
People with a food allergy are often given a device, known as an auto-injector pen, which contains dosages of adrenaline that can be used in case of emergencies.
People with a food allergy are often given a device, known as an auto-injector pen, which contains dosages of adrenaline that can be used in case of emergencies.
When to seek medical advice
If you
suspect you or your child may have a food allergy, it's very important
to ask for a professional diagnosis from your GP, who can refer you
to an allergy clinic.
Many
parents mistakenly assume their child has a food allergy when in fact
their symptoms are due to a completely different condition.
There
are commercial allergy-testing kits available but their use is not recommended.
Many kits are based on unsound scientific principles and even if they are
reliable, it is best to have the results interpreted by a health professional.
Who is
affected
Most
food allergies affect younger children aged under the age of three. It is
estimated that around one child in every 14 children of this age has
one or more food allergies.
Most
children will "outgrow" food allergies to milk, eggs, soya and wheat
by the time they start school.
Peanut
allergies are usually more persistent. An estimated four out of five
children with peanut allergies remain allergic to peanuts for the rest of their
life.
Food
allergies that develop during adulthood, or persist into adulthood, are likely
to be lifelong allergies.
For
reasons that are unclear, rates of food allergies have risen sharply in the
last 20 years.
However,
deaths from anaphylaxis-related food reactions are now very rare. There were
only two reported deaths related to food allergies in England and Wales during
2010.
