A few info sites on peanut allergy:
http://www.allergic-reactions.com/consu ... ut_allergy
http://www.nutfree.com/
http://www.ich.ucl.ac.uk/factsheets/mis ... t_allergy/
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A few excerpts:
...estimate that from 2% to 2.5% of the general population, or 5.4
million to 7 million Americans
have food allergies. About three
million of these are believed to be allergic to peanuts or tree
nuts alone...
What is peanut allergy?
Some people are allergic to proteins found
in peanuts. These proteins are not
destroyed by cooking so both fresh and
cooked and roasted peanuts can cause an
allergic reaction.
Who can develop peanut allergy?
Anyone can develop an allergy to peanuts,
but it is more common in people who have
other atopic conditions, like eczema,
asthma or hay fever, or who have immediate
family with these conditions. Atopic
conditions are allergic conditions which are
inherited.
There is some discussion as to whether
eating peanuts and peanut products in
pregnancy increases the risk of a child
developing peanut allergy. The results are not
conclusive, but the Department of Health
recommends that if a member of the
immediate family has an atopic condition,
the mother should avoid peanuts and
peanut products during pregnancy and
breastfeeding. If you think your child is at risk,
then avoid peanuts or peanut products until
he or she is at least three years old.
The majority of children and 50% of adults
who are allergic to peanuts are allergic to
other nuts, like walnuts, cashews or
brazilnuts. A significant number of people have
multiple allergies and could be allergic to
other nuts like hazelnuts, pine nuts and
pistachio nuts.
What are the symptoms of peanut allergy?
The symptoms vary from person to person.
Most people develop symptoms
immediately after coming into contact with
peanuts. The degree of allergic reaction
also varies from person to person. Some
people are so sensitive that they can have a
reaction after touching another person who
has eaten peanuts, while some feel
unwell whilst in a room where peanuts have
been opened. Some people have a mild
reaction which might include an itchy rash,
tingling on the lips, tongue or roof of your
mouth, stomach pain, diarrhoea or sickness.
However, some people have a more
serious reaction (anaphylaxis) which may
include facial swelling, difficulty breathing,
weakness, and/or collapse. It is important
to recognise that anaphylaxis can occur
with collapse or drowsiness rather than a
rash or difficulty breathing.
What causes peanut allergy?
For people with peanut allergy, coming into
contact with a tiny amount of peanut can
cause the body to have an allergic
reaction. An allergic reaction can be caused by
eating peanut oil, although this is
extremely rare. The anaphylaxis campaign has
more information on peanut-related food
allergy. Food products that do not contain
peanuts as an ingredient may still be
contaminated by traces of peanut from the last
batch of products cooked using the same
equipment.
How common is peanut allergy?
Research estimates that one in every two
hundred people may be allergic to nuts and
the number is growing. About one in a
hundred people may be sensitised, which
means that they produce antibodies to nuts
without ever having had a reaction.
However this sensitisation may progress to
a full blown allergy and should be
monitored regularly.
How can peanut allergy be treated?
Currently, there is no cure for peanut
allergy because it is not possible to desensitise
children with peanut allergy.
People with peanut allergy should avoid
peanuts and food containing peanuts. This
will prevent allergy accidents. There are
many lists of products containing peanuts but
as a general guide you should check the
ingredients lists of:
• baked products, like cakes and
biscuits
• cereals
• oriental dishes
• crackers
• ice creams
• health bars
• pastry
Some restaurants now produce ingredient
lists for their dishes. Always enquire when
you make a reservation. The list may not be
on display, so always ask. If they do not
have an ingredient list, ask to speak to
the chef. A waiter may not know the full
ingredients used in a particular dish. If
in doubt, order another meal that you know is
safe.
The food industry has started to label
foods as ‘not suitable for nut allergy sufferers'
and ‘may contain nuts' but unfortunately
some manufacturers label all foods in this
way rather than risk someone having an
allergic reaction to a food that has not been
labelled.
If you are travelling somewhere by plane,
ring up the airline to ask if they serve
peanuts on board. If it does, contact the
Anaphylaxis Campaign which is producing a
list of which airlines serve peanuts and
which do not.
If you are allergic to peanuts, it is
important that you wear a MedicAlert bracelet or
necklace. These are pieces of jewellery
containing the diagnosis and a telephone
number which any doctor can ring to find
out more about your medical conditions.
This will help medical staff diagnose your
problem and deal with it appropriately if you
have a severe allergic reaction.
It is necessary to tell schools, nurseries
and clubs about your peanut allergy so they
can plan food and activities to take this
into account. Some schools and nurseries
have now banned peanuts and peanut products
from packed lunches .
If you suffer severe allergic reactions or
anaphylaxis to peanuts, your doctor may
advise you always to carry a pre-loaded
epinephrine (adrenaline) syringe. More
details about this are available in our
leaflet on anaphylaxis.
What are the prospects for people with
peanut allergy?
If the suggestions above are followed,
there is no reason why someone with peanut
allergy should not have a normal and
enjoyable life.
We know that about 25% of children who are
allergic to peanuts grow out of their
allergy, while a proportion of children
have milder reactions as they get older.
=================================================================
Food allergy is the most common cause of anaphylaxis outside of the
hospital.1,2 Experts
estimate that from 2% to 2.5% of the
general population, or 5.4 million to 7 million Americans
have food allergies.3 About three
million of these are believed to be allergic to peanuts or tree
nuts alone,3 yet there are other
common food culprits.
The symptoms of food allergies
resemble those of food intolerance and so it is important to
consult a doctor to be diagnosed
correctly. Once diagnosed, you can learn about ways to
prevent and treat your food allergy.
Definition
Food allergies are an increasingly
common cause of anaphylaxis that result in about 125
deaths each year in the United
States.4 Some allergists believe this perceived rise in incidence
may be attributed to increased
exposure to certain foods, such as peanuts, before children's
immune systems are mature enough to
handle them.5,6
Having a food allergy, as with any
other severe allergy, means that a person's immune system
reacts to a protein, in this case a
food protein, as a threatening foreign substance and primes
the body's defenses against it. Each
time the person comes in contact with this protein, his or
her immune system launches an attack
by releasing histamines and other powerful
chemicals. The release of these
chemicals trigger symptoms of an allergic reaction, which can
range from hives to deadly
anaphylaxis.
Histamine is a chemical released by
cells of the immune system called mast cells. It is largely
responsible for producing the
symptoms associated with allergic reactions.
Common Culprits
There are eight types of foods that
are accountable for 90% of all food-allergic reactions.7 The
foods that most commonly cause
anaphylaxis (called allergenic foods) are:
Peanuts
Tree nuts (walnuts, pecans,
etc.)
Shellfish
Fish
Milk
Soy
Wheat
Eggs
Sulfites added to foods can also set
off anaphylactic reactions, as well as exercising, within a
few hours of eating for a small
number of people who do not otherwise experience food-related
anaphylaxis.
Children, who have immature immune
systems compared with adults, are most susceptible to
a broad array of food allergies.
People have been known to outgrow allergies to milk, soy, and
eggs after childhood. However,
peanuts, tree nuts, and shellfish tend to be lifelong food
triggers.5,8,9 In fact, reactions to
these foods may become more serious over time. When
sensitivity exists, the intensity of
a given anaphylactic attack is unpredictable because it
depends on the amount of allergen
contained in the food eaten and the individual's degree of
hypersensitivity to the allergen.8
Also, if someone already has another immune problem, he or
she may be at increased risk for a
strong reaction to the food to which they are allergic. For
example, patients who have asthma or
atopic dermatitis, as well as food allergies, are at
increased risk for severe
anaphylaxis.1,2,10,11
Asthma is a condition in which the
airways narrow due to an allergic hypersensitivity.
Atopic dermatitis is a chronic
condition resulting in itchy inflammation of the skin that is
associated with allergy sufferers.
Symptoms
Symptoms of food allergies can range
from mildly irritating to life threatening. The most
common symptoms of food allergies
are:
Hives
Vomiting
Diarrhea
Abdominal cramping
Other symptoms typical of
anaphylaxis generally include:
Swelling of the throat, lips,
or tongue
Difficulty breathing or
swallowing
Metallic taste or itching in
the mouth
Generalized flushing,
itching, or redness of the skin (hives)
Nausea
Increased heart rate
Plunging blood pressure (and
accompanying paleness)
Sudden feeling of weakness
Anxiety or an overwhelming
sense of doom
Collapse
Loss of consciousness
For some people with food allergies,
just a taste or even a touch of the foods to which they are
allergic can result in any of these
symptoms and can set off a chain reaction that takes only
minutes to culminate in full-blown
anaphylaxis: swelling of the airways, loss of blood pressure,
loss of consciousness, shock, and
even death.12 This can happen with their first known
exposure to a food. There have even
been rare cases documented in which inhalation
exposure to a food has triggered an
anaphylactic reaction.13 The more rapidly symptoms
present themselves; the more likely
the reaction is to be severe.13
Intolerance Versus Allergy
Food allergy and intolerance are
often mistaken for one another. While they may share similar
symptoms, including diarrhea and
vomiting, food allergy is an immune system response while
food intolerance occurs when another
system of the body (usually the digestive tract) reacts
adversely to a food.
For example, one of the most common
food intolerances arises in response to lactose, the
sugar in milk. Lactose intolerance
occurs when a person lacks an enzyme needed to digest
this sugar, and the body reacts with
gas, bloating, diarrhea, and abdominal pain when milk
products containing lactose are
consumed. When these symptoms occur as a result of
intolerance rather than allergy,
they do not indicate an anaphylactic reaction. However, anyone
who has such symptoms should seek
proper medical care to get a diagnosis and counseling
in order to determine what dietary
and medical measures are needed.
Diagnosis
A person who has experienced even
mild allergic reactions to food should seek a professional
diagnosis by a board-certified
allergist (see Find an Allergist to locate an allergist near you). To
make a proper diagnosis, the
allergist will record a complete history of the symptoms, which
foods were eaten, how much of the
food was eaten, and how soon afterward the symptoms
began. The doctor may also decide to
perform a skin prick test, RAST (blood test), or oral food
challenge to confirm the diagnosis.
A skin prick test may be used to
identify allergens. This test involves injecting tiny amounts of
diluted food solutions into the
skin. If the person is allergic to the particular food sample
injected, then the skin will react
within 15 to 20 minutes—usually with a hive-like swelling
surrounded by redness.
RAST, or radioallergosorbent test,
directly measures antibodies specific to allergens in the
blood.
Prevention and Treatment
In most cases, there is no cure for
food allergies. Therefore, it is essential that people with food
allergies protect themselves by
carefully avoiding the foods that trigger their reactions, and by
being prepared to treat anaphylactic
reactions that occur immediately with epinephrine in
combination with emergency medical
care.
Avoidance
Avoidance of foods that trigger
allergic reactions is critical and more challenging than one
might expect. While steering clear
of a food in its isolated form may not be so difficult, people
with allergies, or the parents of
children with food allergies, must know to check product labels
for alternate names of food
ingredients that may contain their allergens. People who have food
allergies must also try to avoid
foods that may contain hidden ingredients or that may have
been prepared using equipment
contaminated by an allergenic food.
Since it is often difficult to avoid
hidden foods—and because it is often difficult for children to
resist sharing foods—it's important
that an allergic person's family, friends, and teachers know
about, and understand, the
ramifications of food allergy, so they can aid in the prevention of
anaphylaxis and be ready to assist
should an emergency arise.
Epinephrine
Exposure to allergenic foods is
sometimes unavoidable, so people with food allergies need to
be prepared to treat allergic
reactions. The treatment of choice for severe allergic reactions to
food, which can swiftly lead to
anaphylaxis, is an immediate injection of epinephrine followed
by emergency medical attention.14
Many physicians also recommend taking antihistamines
such as diphenhydramine to relieve
the symptoms of allergic reactions, but antihistamines are
not a substitute for epinephrine.
Only epinephrine can stop the potentially deadly effects of
anaphylaxis.
A 1992 study of children and
adolescents with food allergy demonstrates how important it is for
people with food allergies to carry
epinephrine at all times.10 According to the study, 10 out of
13 fatal and near-fatal anaphylactic
reactions to food occurred in public places, and none of the
adolescents and children who died
had epinephrine with them. All of the adolescents and
children who survived received
epinephrine before or within 5 minutes of developing severe
symptoms.10 Other studies agree with
these findings.11 Thus, all individuals with food
allergies should carry
self-injectable epinephrine, such as the EpiPen® or EpiPen® Jr
auto-injector, with them at all
times.
Since immediate administration of
epinephrine can be the difference between life and death,
parents of children with
life-threatening food allergies should alert their child's school of the
particular allergen, and make sure
their child's teachers and caregivers have an epinephrine
auto-injector on hand and know how
to administer it.
Side effects of epinephrine may
include palpitations, tachycardia (an abnormally fast
heartbeat), sweating, nausea and
vomiting, and respiratory difficulty. Cardiac arrhythmias may
follow administration of
epinephrine. Therefore, patients should ask their doctors about the
circumstances under which this
life-saving medication should be used.
You and your child should also ask
your physicians whether antihistamines should be carried
in addition to epinephrine. Wearing
a medical identification bracelet describing your allergies
and susceptibility to anaphylaxis
can help ensure prompt, proper treatment during an
emergency.
Emergency medical care
Even after administering
epinephrine, emergency medical treatment should be sought at once
because severely allergic people
experiencing anaphylaxis may need emergency respiratory or
cardiac care, or even need to be
resuscitated if they stop breathing altogether. More commonly,
these patients will need
professional care to determine whether additional epinephrine,
steroids, antihistamines, or other
treatments are required. In either case, follow-up diagnosis
and care by medical professionals
after administration of epinephrine is critical to recovery.
Delayed or secondary reactions do
occur, and patients should remain under medical
supervision for at least 4 hours
after an episode of anaphylaxis.8
References
1.Kemp SF, Lockey RF, Wolf BL,
Leiberman P. Anaphylaxis: a review of 266 cases. Arch
Intern Med. 1995;1749.
2.Yocum MW, Khan DA. Assessment
of patients who have experienced anaphylaxis: a
3-year survey. Mayo Clinic
Proc. 1994;69:16-23.
3.Sicherer SH, Munoz-Furlong A,
Burke AW, et al. Prevalence of peanut and tree nut
allergy in the US determined
by a random digit dial telephone survey. J Allergy Clin
Immunol. 2000;103:559-562.
4.Burks AW, Sampson HA.
Anaphylaxis and food allergy. In: DD Metcalf, HA Sampson, RA
Simon, eds. Food Allergy:
Adverse Reactions to Foods and Food Additives. 2nd ed.
Malden, Mass: Blackwell
Science; 1997.
5.Sampson HA. Food allergy:
primer on allergic and immunologic diseases. JAMA.
1997;288:1888-1894.
6.Dr. Nancy Snyderman.
Interviewed on Good Morning America. ABC-TV; September 20,
1998.
7.Food Allergy Network. Facts
and Fiction. Available at:
www.foodallergy.org/facts_fiction.html.
8.Wood RA. Anaphylaxis in
children. Patient Care. 1997;31(13):161.
9.Anderson JA. Milk, eggs and
peanuts: food allergies in children. Am Fam Physician.
1997;56(5):1365.
10.Sampson H, Mendelson L, Rosen
J. Fatal and near-fatal anaphylactic reactions to food
in children and adolescents.
N Engl J Med. 1992;327:380-384.
11.Yunginger JW, Sweeney KG,
Sturner WQ, et al. Fatal food-induced anaphylaxis. JAMA.
1988;260:1450.
12.The Merck Manual. 16th ed.
Merck Research Laboratories. 1992:331.
13.Joint Task Force on Practice
Parameters, American Academy of Allergy, Asthma and
Immunology, American College
of Allergy, Asthma & Immunology, and the Joint Council
of Allergy, Asthma and
Immunology. The diagnosis and management of anaphylaxis. J
Allergy Clin Immunol.
1998;101(6 pt 2):S465-S528.
14.AAAAI. The use of epinephrine
in the treatment of anaphylaxis. Position statement #26.
Available at:
www.aaaai.org.