Wednesday, January 9, 2013

Understanding Anaphylaxis

Anaphylaxis (pronounced ANA-FALL-AXIS) is a life-threatening, whole body, allergic reaction to a chemical substance (MedlinePlus).  The reaction can be swift and catastrophic if not treated quickly.  Anaphylaxis occurs when exposed to an allergen and the body becomes sensitized to it.  Subsequent exposure results in a systemic immune response, the releasing of histamine, and resulting in a typical physical response.  Signs and symptoms of a typical reaction include hives, difficulty breathing, itching, swelling of lips, face, and/or tongue among others. 

Anaphylaxis can occur in response to any allergen, but is most rare in response to pollen and other inhaled allergens.  Allergies that are more likely to cause anaphylaxis are drug allergies, food allergies, and insect bites/stings. 

According to the CDC approximately 4% - 6% of children under 18 years old suffer from food allergies.  The prevalence of allergies is also on the rise, but the reasons for the increase are unknown.  Eight types of food account for 90% of all food allergy reactions:  cow’s milk, eggs, peanuts, tree nuts (walnuts, pecans, hazelnuts, etc.), fish, shellfish, soybeans, and wheat.  The CDC has paid particular attention to limiting accidental exposure to food allergens for children in school, as this has been of particular concern.

Drug allergies result in the same allergic response from the body as other allergens.  Most often, this reaction results in a mild rash and hives, but a severe anaphylaxis reaction is possible.  According to the NIH penicillin (and other antibiotics) are the most common cause of drug allergies.  Other drug classes that can cause an allergic response are anticonvulsants, insulin (especially animal based), iodinated x-ray contrast dyes, and sulfa drugs.  Severe allergic reactions to medication, overdoses, or other negative responses to medication are referred to “adverse drug events.”  To learn more about adverse drug events in children check out the information provided by the CDC.

When stung by an insect there is typically an immediate reaction of minor redness and itching.  For most people, the reaction ends and over a period of days the bite site begins to heal.  For someone who has an anaphylactic response to an insect bite the pain, redness and swelling will likely be much more severe and the person may report difficulty breathing.  The most common insects that cause an anaphylactic response are bees, wasps, hornets, and spiders.

If you are in a situation, where you suspect anaphylaxis the most important thing you can do is call 911 and initiate the emergency medical system (EMS).  You should also assess whether or not the individual is having difficulty breathing, if so monitor ABCs (airway, breathing, and circulation) until EMS arrives and be prepared to initiate rescue breathing or CPR as necessary.  It is also important to understand what allergy may be causing the reaction so that you can provide appropriate first aid.  Here is a list of key steps for the immediate care for someone suffering for anaphylaxis:
  • Activate EMS
  • Assess ABCs and initiate rescue breathing and CPR as necessary
  • If having difficulty breathing monitor for worsening symptoms and do not give food or drink
  • If available, instruct victim (or if necessary assist victim) in administering epi-pen
    • victims with known severe food or insect bite allergies may have an epi-pen available
  • If reaction is because of an insect sting, remove the stinger using a stiff card (such as credit card or driver’s license, do NOT use tweezers)
  • Remove any restricting clothing or jewelry around area of potential swelling to limit additional complications
  • Monitor victim until EMS arrives

For more specific information on how to treat a typical allergic reaction check out the information made available by the NIH for food allergies, drug allergies and bee/insect bites.

There are many situations where people are unaware that they have an allergy until they have their first adverse reaction making prevention impossible in these cases.  For someone with a diagnosed allergy, especially a severe one, it is very important that all effort be made to avoid contact with or ingestion of the allergen.  In many cases, individuals with severe allergies are encouraged to wear a medical alert bracelet and have an epi-pen available at all times. 

How food allergies develop are not fully understood although some research shows that breast feeding infants and delaying the introduction of common allergy inducing foods to infants until their gastrointestional tracts are mature enough to handle them (this varies by food) can help decrease the likelihood of allergies.  Once an allergy becomes known, the best prevention is to avoid the food you are allergic too.

Similar to food allergies, drug allergies should be prevented by avoiding the offending medication and often, similar medications (those in the same class). 

Finally, to minimize the possibility of being stung by a bee or other insect there are several things you can do.  Most importantly, when eating outside do not hang around garbage cans or near a large number of sweet drinks or foods.  You should also avoid wearing floral perfumes and dark or floral patterned clothing.


Submitted by Heather L. Clemons, M S, MBA, ATC

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