Exercise: Although less common, exercise can cause a
physical allergy that leads to anaphylaxis. The digestion of
certain foods or medications prior to exercise can be a
contributing factor. Shrimp and celery, as well as aspirin and
other NSAIDs, are the most common culprits.
If you have experienced exercise-induced anaphylaxis after
eating or taking medication, you should avoid exercise for four to
six hours after digesting the problem substance. Exercising in
areas where other people are present, as well as carrying a self-injectable
shot of epinephrine with you during exercise and wearing a medical
bracelet that identifies your condition, are strategies that can
help you to receive quick treatment in case of an emergency.
Pinpointing the Anaphylactic Trigger
Your best bet for avoiding future anaphylactic episodes is to
identify and avoid your triggers. The observations of friends and
family present during a past anaphylactic episode can be very
helpful in narrowing down the list of possible triggers. Any
substances or foods you may have come into contact with in the
hours leading up to an anaphylactic episode are suspects. In
making your list, be very detailed. It's not enough to say
"hot dog," for example. Contact the manufacturer and
find out exactly what's in it.
If there is not an obvious culprit, an allergist-immunologist
can test you for some of the more common triggers. Skin testing
can be done for most foods, antibiotics (including penicillin) and
insect venoms. A positive reaction results in an area of swelling,
redness and itching at the site of the skin test.
If skin testing can't be done for some reason, or if the
results of skin testing are inconclusive or skin testing is not
available for the suspected allergen, it may be necessary to do an
allergy blood test or a challenge test. Challenge tests involve
introducing increasing amounts of the suspected allergen into your
body through injection, inhalation or digestion. Any signs of an
allergic reaction during the challenge indicate that you are
allergic to the substance. If you had a negative skin test or
blood test but a positive reaction to the challenge test, you are
still considered sensitive to the substance - it just might take
more substantial amounts of the allergen for your body to have a
reaction.
Food: While food allergies can develop at any age,
reactions are most common in children. Even then, only 2 percent
to 5 percent of children have diagnosed food allergies. Peanuts,
tree nuts, fish, shellfish, milk and eggs are the most common
culprits of severe reactions, although virtually any food or food
component can cause anaphylaxis. It is possible for foods that
have previously been eaten with no problem to trigger an
anaphylactic episode.
Anaphylactic symptoms usually occur immediately after eating
the problem food — although it is possible for symptoms to
subside and then reappear several hours later. In extremely
allergic individuals, even inhaling tiny food particles can induce
a reaction.
The best way to prevent food-induced anaphylaxis is to avoid
your trigger food or foods. Check ingredient labels carefully and
be especially cautious when eating out. Restaurant staff often are
unaware of the full list of ingredients in a dish. If your child
has a severe food allergy, make sure his or her school is prepared
with an emergency plan of care and a shot of epinephrine in case
of an unexpected anaphylactic attack.
Anaphylaxis
Most people go through life without ever experiencing anaphylaxis
— a rare but severe allergic reaction that occurs suddenly and
can be life threatening. Anaphylaxis can happen moments, or even
seconds, after being exposed to a triggering substance. For
example, you may experience anaphylaxis directly following an
insect sting or a penicillin shot. Because an anaphylactic episode
can progress quickly, it is important to know the warning signs
and prepare for an emergency episode if you have had an episode in
the past.
What Is anaphylaxis?
Anaphylaxis, also known as anaphylactic shock, is your body's
overreaction to a foreign substance. Your immune system responds
by producing an abundance of antibodies, which are a type of
protein created by the white blood cells, to fight the foreign
substance. These antibodies, called immunoglobulin E (IgE), cause
specific cells to release chemical substances that can be harmful.
The release of these chemicals causes allergic symptoms. In the
case of anaphylaxis, this can include drastic changes to
circulation and air passages similar to those experienced when
someone goes into shock.
An anaphylactoid reaction is another type of immediate reaction
that mimics anaphylaxis. While symptoms and treatments are the
same, the reason for the reaction is not. An anaphylactoid
reaction does not involve the IgE antibodies or the immune system
and is not considered a true allergic reaction. Even so, the
reaction can be just as serious.
Symptoms
The symptoms and course of anaphylaxis can vary. Initial signs
of an anaphylactic episode can be deceptively mild, such as a
runny nose, a skin rash all over the body, or a nondescript
"strange feeling." These symptoms can quickly become
more serious, including difficulty breathing, swelling of the
throat or other parts of the body, rapid drop in blood pressure,
and dizziness or unconsciousness.
Other symptoms of anaphylaxis include:
Sense of impending doom
Hives
Tightness of the throat
Hoarse voice
Nausea
Vomiting
Abdominal pain
Diarrhea
Lightheadedness
Cardiac effects, including a rapid drop in blood pressure
and irregular heart beat
It is important to seek immediate emergency medical care if you or
someone you know begins to go into anaphylactic shock. If the
person loses consciousness, raise their feet while waiting for
medical assistance. Keep them warm and make sure their airway
remains open. If they seem to be having trouble breathing, lay
them on the ground and tilt their head back. This helps get the
tongue out of the way of air flow.
Emergency Treatment
In the most serious cases of anaphylaxis, your heart can stop
pumping blood (a condition known as cardiovascular collapse).
Cardiovascular collapse happens when there is a rapid loss of
blood pressure, and your tissues and organs do not get enough
fluids and oxygen. It is considered the "shock" part of
anaphylactic shock. If this occurs, your doctor will administer
large volumes of intravenous fluids to bring your blood pressure
back to normal.
Epinephrine is the most commonly used emergency treatment for
anaphylaxis. Epinephrine constricts blood vessels in the digestive
tract and skin and raises blood pressure. It also widens the air
passages to make breathing easier. If epinephrine doesn't ease
breathing, your doctor may insert a breathing tube to keep the
airway open
It is important to know that the earlier epinephrine is given,
the more effective it is at stopping the reaction. Symptoms
usually improve quickly after epinephrine is administered.
Although epinephrine acts fast, its effects are short-lived. If
you are having an anaphylactic episode, your doctor may give you
second and third doses of epinephrine over several hours to
control symptoms. Epinephrine is usually administered as an
injection, but it can also be inhaled with a special device.
Epinephrine is sometimes given with other drugs, such as
corticosteroids and antihistamines. These medications can't stop
an anaphylactic episode, but they are useful in treating some of
the symptoms associated with anaphylaxis, such as swelling of body
parts and itching.
People on blood pressure medications, such as ACE inhibitors
and beta-blockers, may not respond to epinephrine. Epinephrine
constricts blood vessels, while ACE inhibitors and beta-blockers
prevent blood vessel constriction. Patients on these blood
pressure medications may respond better to other first-line
anaphylaxis drugs. If you are on blood pressure medication or any
other prescription medications, you should wear identification
that indicates what drugs you are taking, such as a Medic Alert®
bracelet.
If you visit an emergency room for anaphylaxis, you may given a
prescription for an easy-to-use, self-injectable shot of
epinephrine (Epipen® or Epipen Jr®). You
should carry this shot with you at all times in case of an
emergency anaphylactic episode. Have someone show you how to use
it correctly, and read the information on the shot insert when you
get home. Injecting the epinephrine in the wrong place can have
serious consequences. Always seek medical attention immediately
after using a self-injectable shot of epinephrine since one shot
may not be enough to stop an anaphylactic reaction and other
medications may be required.
Triggers
The most common anaphylactic and anaphylactoid triggers include
medications, foods, insect stings and bites, and latex. Other
triggers include diagnostic testing materials, exercise,
progesterone (a natural hormone) and seminal fluid. In extremely
rare cases, extended exposure to strong sunlight can cause
anaphylactic shock.
Drug Allergies: Drug-induced anaphylaxis comes on fast
— usually within minutes or even seconds after the offending
medication is given. The most severe reactions usually happen when
the medication is administered directly into the bloodstream —
through an injection or shot — rather than when taken orally.
The most frequent cause of anaphylaxis is penicillin, a
commonly used antibiotic responsible for approximately 75 percent
of medicine-induced anaphylaxis deaths in the United States. A
patient who has had a prior reaction to penicillin is six times
more likely to experience a future reaction.
Other antibiotics, anesthetics (medications used to sedate or
numb an area during surgery), protamine (medication used to
counter the effects of heparin, a blood-thinning medication) and
insulin also can act as anaphylactic triggers. Anaphylactoid
(anaphylactic-like) reactions can occur after taking aspirin (nonsteroidal
anti-inflammatory drugs, or NSAIDs) and from radiographic contrast
material used for diagnostic testing.
In most cases, if you have had an anaphylactic or anaphylactoid
reaction to a drug in the past, you should avoid this medication
in the future, and you should get a medical bracelet identifying
your allergy. Your doctor can help determine which medications you
can use as a safe alternative as well as any other medications
that you should avoid.
If you develop a serious infection for which there are no
alternative medications, your doctor may suggest desensitization.
This process begins with a small dose of the medication to which
you have had a reaction. As your body becomes tolerant, the dosage
is gradually increased over time. Because there is a chance of
anaphylaxis, this should only be done with appropriate monitoring
by your doctor. The effects of desensitization are usually
temporary. If you need the medication again in the future, the
desensitization process may need to be repeated.
Idiopathic Anaphylaxis
In about 50 percent of anaphylactic episodes, patients and
doctors are unable to pinpoint the cause. When a specific trigger
can't be identified, the anaphylaxis is said to be
"idiopathic," which means "without known
cause."
Idiopathic episodes are indistinguishable from anaphylactic
episodes where a cause is eventually determined. The only
difference between regular and idiopathic anaphylaxis is that
people who have had idiopathic episodes are unable to avoid their
triggers because they don't know what they are. These people
sometimes live in fear of having another unexplained episode.
Carrying self-injectable epinephrine shots and educating family
and friends about what to do in case of an anaphylactic episode
can help minimize this fear. In addition, keeping a diary and
being very aware of events that occur before episodes may
ultimately help you find a trigger.
What To Do If You Have Had an Anaphylactic Episode:
If you have had an anaphylactic reaction in the past:
Know your triggers. Avoiding the substances to which you are
allergic is the most effective way to prevent future
anaphylactic episodes.
Know what to do if you unexpectedly come into contact with
your trigger. Your doctor can help you develop a detailed plan
of emergency care.
Educate family and friends on what to do if you begin to
have an anaphylactic episode.
If your doctor has prescribed a self-injectable shot of
epinephrine, carry it with you at all times.
Wear a medical bracelet that indicates your anaphylactic
triggers. These bracelets can provide crucial information in
the case of an emergency.
Insect stings and bites: While beneficial in certain
situations, insects can cause considerable discomfort and
sometimes even death to people who are allergic to their venom.
Anaphylactic reactions to insect venom occur in 0.5 percent to 5
percent of the U.S. population and account for about 40 deaths
each year.
Insects known to trigger anaphylaxis include:
Honeybees
Yellow jackets
White-faced hornets
Yellow hornets
Wasps
Imported Fire Ants (southern United States)
Although anaphylaxis usually occurs after multiple bites or
stings, even a single sting can be life-threatening in highly
allergic people. If someone has previously had an insect-sting
reaction, they have a 60 percent chance of a comparable or more
severe reaction if stung again.
Even if you're not allergic to insect venom, it is common to
have swelling, redness and itching at the bite or sting site.
These symptoms usually persist for a few days and then go away.
Cleaning the area and applying ice can help reduce discomfort.
You can help reduce your chances of being stung by not wearing
strong perfumes or brightly colored clothing. Long pants and
sleeves can give you added protection.
Immunotherapy, or "allergy shots," is the only
treatment that can reduce the possibility of future anaphylaxis
caused by insect venom. Immunotherapy involves injections of venom
(or fire ant whole-body extract) in gradually increasing amounts
over the course of several months or sometimes years.
If you undergo immunotherapy for insect venom, your
allergist-immunologist will inject tiny amounts of the venom that
caused your anaphylactic episode under your skin once or twice a
week. Initially, there may be a small amount of swelling and
itching at the injection site. Over time, these symptoms should
stop completely, indicating that you are becoming desensitized. As
you are able to tolerate increasing amounts of the venom, the
frequency of treatments will be decreased to once or twice a
month. Eventually, the shots can be stopped altogether.
Immunotherapy treatments usually continue for three to five years
or longer.
After being treated with immunotherapy, you should still try to
avoid stinging or biting insects. However, if you accidentally
encounter an insect that stings or bites you, chances of having an
anaphylactic attack will be greatly reduced.
While unlikely, immunotherapy does carry a small risk of
anaphylaxis. Because of this, allergy shots should only be given
under close observation of a medical professional.
Latex: Anaphylactic and allergic reactions to latex have
become more common in recent decades because of an increased use
of latex in medical products. Latex allergies are most commonly
caused by natural latex derived from the Hevea brasiliensis tree,
rather than from synthetic latex. Allergies to synthetic latex are
very rare.
Products containing natural latex, which is most commonly the
cause of allergies, include:
Disposable gloves
Intravenous tubes
Airway tubes
Syringes
Stethoscopes
Adhesive tapes
Catheters
Health-care workers, children with spina bifida, people with
urinary tract abnormalities, and people whose work brings them
into constant contact with natural latex are at a higher risk for
latex-induced allergies. People who have had prior allergic
reactions to latex and people who have had unexplained
anaphylactic episodes during a medical procedure also may be at
higher risk for latex-induced anaphylaxis.
Before any medical procedure, it is important to inform your
doctor or dentist about any allergies you may have, especially to
latex. If you have spina bifada (with or without a known latex
allergy) or a history of latex allergy, you should request that
all dental, medical and surgical procedures be done in an
environment where latex-free gloves are used and care is taken so
that you do not come into contact with latex medical accessories,
such as catheters or adhesives.
