Anaphylaxis

Anaphylaxis or anaphylactic shock is a severe, fast acting and possibly life-threatening allergic reaction. According to the American Academy of Allergy Asthma & Immunology (AAAAI) anaphylaxis is triggered the same way other allergies (Read about "Allergies") are - the body's immune system (Read about "The Immune System") overacts to a substance generally considered harmless. In anaphylaxis, however, this response is dramatic due to extreme hypersensitivity. This can cause a severe allergic reaction or anaphylactic shock. It usually involves various parts of the body and if severe enough, it can be fatal. The numbers vary widely depending on the cause of the reaction but the National Institute for Allergy and Infectious Diseases (NIAID) says as many as 600 people a year die from anaphylaxis: the largest group, about 400, from a reaction to penicillin. Another 100 - usually children - die from food allergies, and 100 others from insect bites. (Read about "Food Allergies" "Insect Bites") A small, but growing number of people react to latex. (Read about "Latex Allergy")

Causes

Like the majority of other allergic reactions, anaphylaxis is caused by the release of histamine and other chemicals from mast cells (part of the body's defense system). A variety of substances can trigger this massive immune response. AAAAI lists some of the more common ones:

• Food - Although any food can cause an anaphylactic reaction, peanuts, tree nuts, milk, eggs, soy, wheat and shellfish top the list. AAAAI also reports food additives like sulfites are common triggers of anaphylaxis. (Read about "Food Allergies")
• Drugs - These can include antibiotics like penicillin, muscle relaxants, insulin, aspirin, anti seizure medicines (Read about "Seizures") or certain post-surgery fluids. (Read about "Medicine Safety")
• Stinging insects - Bees, wasps, hornets, yellow jackets, bed bugs, fire ants and harvester ants are among the insects listed. (Read about "Insect Bites" "Bed Bugs")
• Latex - Most sufferers of latex anaphylaxis are those who have had multiple contacts with latex products during medical procedures. Those susceptible are healthcare workers or patients like children with spina bifida (Read about spina bifida in "Neural Tube Defects") who require numerous surgeries or hospital stays. (Read about "Latex Allergy")
• Exercise - This occurs most often after consumption of an allergy-provoking food.

Some anaphylactic reactions are classified as idiopathic, meaning there appears to be no known cause.

Symptoms: Things to watch for

The symptoms of anaphylaxis can emerge suddenly. They can affect many different parts of the body and progress rapidly. In extreme cases anaphylaxsis can result in cardiac arrest. (Read about "Cardiac Arrest") According to The Food Allergy & Anaphylaxis Network (FAAN), symptoms may begin in as little as five minutes or up to two hours after exposure to the allergen and life threatening reactions can progress over hours. AAAAI lists these typical symptoms:

• nausea and vomiting
• itchy skin
• a feeling of warmth
• hives (Read about "Hives")
• abdominal cramps
• sneezing and coughing
• swelling of the lips, tongue and throat
• severe headache
• diarrhea (Read about "Diarrhea")
• anxiety
• chest pain and tightness
• difficulty swallowing

AAAAI also lists several dangerous symptoms, all of which if severe enough, can be fatal. These include:

• difficulty breathing (Read about "Respiratory System")
• a drop in blood pressure
• shock
• loss of consciousness

Treatment

Because anaphylaxis can progress so quickly, the first signs of reaction should be taken seriously. Do not wait to see how serious the reaction may become. Call for emergency help immediately. (Read about "Emergencies")

Emergency treatment of anaphylaxis usually involves an injection of adrenaline (epinephrine). Adrenaline acts quickly to reverse the effects of histamine by constricting blood vessels. This reduces swelling, improves breathing and stimulates the heartbeat to maintain blood pressure. Other medications such as antihistamines and steroids can then be administered to help ensure that symptoms do not return. The FAAN has what it calls "3 R's for treating anaphylaxis":

• Recognize the symptoms
• React quickly
• Review what happened to prevent reoccurrence

The American Academy of Family Physicians (AAFP) recommends that, even with emergency treatment, a person with an anaphylaxis reaction should be transported to the hospital for further evaluation and treatment as soon as possible.

Preventing anaphylaxis

Avoiding the allergic triggers is the only reliable method of preventing anaphylaxis. AAAAI has these recommendations:

• For insect allergies, avoid spending time outdoors during insect season. Learn to recognize and avoid likely nest sites and ask about the possibility of receiving "allergy shots" which can protect against future allergic reaction.
• Preventing food allergies requires knowledge of prepared foods or dishes in which the allergen is likely to occur. Question ingredients when dining out. (Read about "Food Labels")
• Use of an emergency medical tag detailing drug allergies is vital to preventing inadvertent administration during a medical emergency. Consider wearing a special bracelet or necklace that identifies you as having a severe allergy.
• If you are allergic to latex, avoid contact with natural rubber latex products.

AAFP also recommends those who have had an anaphylaxis reaction should see an allergist for follow-up evaluation and treatment. An allergist can prescribe a self-injectable adrenaline shot to carry with you as a short-term treatment.

You may also want to inform family, healthcare workers, employers and school officials about any severe allergies so they can watch for symptoms and help you avoid allergy triggers.

Related Information:

    Drug Interaction Precautions