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What is anaphylaxis?
Anaphylaxis is a
severe, life-threatening allergic response. The immune system creates specific
immunoglobulin E (IgE) antibodies (which are normally made to fight disease) toward a substance
that is normally harmless. The body becomes sensitized to this substance, but
when the person is exposed to it again, the IgE antibodies go into action,
releasing large amounts of histamines. Histamines cause serious reactions
throughout the body, including swelling, hives, lowered blood pressure, and
dilated blood vessels.
In severe cases, a person will go into anaphylactic
shock. Blood pressure drops severely and swelling occurs in the bronchial
tissues, causing the person to choke and lose consciousness. If anaphylactic
shock isn't treated immediately, it can be fatal.
What are the symptoms of anaphylaxis?
Anaphylaxis
may begin with severe itching of the eyes or face and within minutes progress to
more serious symptoms, including:
- swelling, which can cause difficulty swallowing and breathing
- abdominal pain
- cramps
- vomiting
- diarrhea
- hives and angioedema (hives in the throat).
If you have symptoms of anaphylaxis, seek
immediate medical attention, as the condition can quickly result in an increased
heart rate, sudden weakness, a drop in blood pressure, shock, and ultimately
unconsciousness.
What are the most common causes of anaphylaxis?
Food
is generally the most common cause of anaphylaxis--especially peanuts, tree nuts (almond,
walnut, hazel, Brazil, and cashews), shellfish (shrimp, lobster), dairy products,
egg whites, and sesame seeds. Wasp or bee stings are also common causes of
anaphylaxis.
Some substances can cause reactions, called anaphylactoid reactions, that are
similar to and just as serious as anaphylaxis, but do not involve IgE
antibodies. Acetylsalicylic acid (aspirin), nonsteroidal anti-inflammatory
drugs, and radiocontrast dye are common causes of
these reactions.
Pollens and other inhaled allergens (allergy-causing substances) rarely cause
anaphylaxis.
How is anaphylaxis diagnosed?
Anaphylaxis
is diagnosed based on its symptoms. People with a history of allergic reaction
may have a greater risk for developing a severe reaction in the future.
Skin testing and RAST blood tests may help confirm the substances that cause
severe allergic reactions. However, if anaphylactic reactions are suspected,
these tests may not be recommended.
How is anaphylaxis treated?
The only
effective treatment for anaphylaxis is epinephrine (adrenaline) by injection.
Epinephrine works quickly to reverse anaphylactic
symptoms. Epinephrine is typically given through an automatic injection device.
The most common injection site is the thigh.
If you are near someone who is going into anaphylactic shock, call for
professional medical help immediately. CPR and other lifesaving measures may be
required. This may include placing a tube through the nose or mouth into the
airway (endotracheal intubation) or emergency surgery to place a tube directly
into the trachea (tracheostomy).
In addition to epinephrine, treatment for shock includes intravenous fluids
and medications that support the actions of the heart and circulatory system.
After a person in shock is stabilized, antihistamines such as diphenhydramine
may be given to further reduce symptoms.
Living with allergies
If you are
allergic to bee stings or any substances that cause anaphylaxis, you should
always be prepared. Carry an epinephrine injection kit with you at all times.
Also, if you have any drug allergies, you should always inform your health care
provider before undergoing any type of treatment, including dental care. It is
also a good idea to either wear jewelry or carry a card that identifies your
allergy. In cases of emergency, it could save your life.
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