Food Allergies: Treating Severe Allergic Reactions

An allergic reaction in an outdoor setting can rapidly  become a life-threatening emergency. While most of us think of food allergies  as annoyances, they can be quite serious or even life threatening. Itchy skin  rashes can progress to breathing difficulty, swollen soft tissues (e.g., lips,  tongue, throat) that compromise the airway, and low blood pressure or even  shock. Therefore, ita??s important to be familiar with the signs and symptoms of  severe allergy and to be prepared to respond rapidly in the event of an  emergency.

An EpiPen (an epinephrine auto-injector)

The National Institute of Allergy and Infectious Diseases  has released Food Allergy Guidelines for healthcare professionals to help guide  the care of patients with life-threatening food allergies. The full guidelines can be found at http://www.niaid.nih.gov/topics/foodallergy/clinical/Pages/default.aspx. Here are??some key points:

Emergency Care

The first-line treatment for a very severe allergic reaction  (anaphylaxis) is an injection of intramuscular (IM) epinephrine (adrenalin).  Failure to administer epinephrine early in the course of treatment has been  repeatedly implicated in fatalities from anaphylaxis.

IM epinephrine  (given in the front or side of a big muscle of the thigh, e.g., the  vastus lateralis muscle)??is recommended over injection into subcutaneous  tissues because this method of injection provides a more rapid increase in  bloodstream and tissue concentrations of epinephrine.?? When a 1:1,000 epinephrine solution (this is  a standard preparation) is used, the recommended dose is 0.01 mg/kg with a  maximum dose of 0.5 mg. Autoinjectors, such as the EpiPen, typically are  preloaded to deliver 0.3 mg for adults and 0.15 mg for children.

Epinephrine has an onset of action within minutes but is  rapidly broken down in the body. Therefore, the effect is often short-lived?-?-a??repeated  doses may be necessary. If a patient responds poorly to the initial dose or has  ongoing or progressive symptoms despite initial dosing, repeated dosing may be  required after five to 15 minutes. 10 percent to 20 percent of persons who  receive epinephrine will require more than one dose before recovery from  symptoms.

Additional Medications

These medications are often given at the same time as  epinephrine. They are not meant to be given sequentially as listed, with the  exception of epinephrine as first-line treatment.

Antihistamines

a??H1a?? antihistamines are useful only for relieving  itching and the raised red rash (wheals) of an allergic reaction. They do not  relieve airway obstruction caused by tissue swelling, shortness of breath,  wheezing, gastroenteric symptoms, or low blood pressure. Therefore, they should  be considered additional therapy and should  not be substituted for epinephrine.

Bronchodilator Medications

For the treatment of bronchial spasm that is not responsive  to IM epinephrine, inhaled bronchodilators, such as albuterol, should be used  as needed and should be considered to be additional therapy to the  administration of epinephrine.

Corticosteroids

Very little information is available to support or refute  the use of corticosteroids (a??steroidsa??) for the treatment of acute anaphylaxis.  However, their use is prevalent and supported by many health care  professionals. Corticosteroids are not helpful in the treatment of acute  anaphylaxis due to their slow onset of action (four to six hours). These agents  often are given because of their anti-inflammatory properties that benefit recovery  from allergic and inflammatory disease, and also because they may help prevent  waxing and waning, or prolonged, reactions, which occur in up to 20 percent of  afflicted persons.

IV fluids

Many patients with severe allergic reactions require  infusion of intravenous (IV) fluids. Massive fluid shifts can occur rapidly in  anaphylaxis due to leaky blood vessels.??  Any patient whose low blood pressure does not respond promptly and  completely to injected epinephrine should receive large-volume fluid  resuscitation, with normal saline being the preferred treatment. Large-volume  fluid resuscitation should be initiated immediately in patients who present  with a severe drop in blood pressure when moving from the lying-down to the  upright (standing) position, low blood pressure in any position, or incomplete  response (with respect to blood pressure) to IM epinephrine.

Supplemental Oxygen Therapy

Oxygen should be administered initially to all patients  experiencing anaphylaxis.

Patient Positioning

The patient should be placed in a lying-down position (if  tolerated) with the lower limbs raised. Persons with breathing difficulty or  vomiting may not tolerate a recumbent position.

Anaphylaxis

Anaphylaxis has many different symptoms, and can even look  like a severe asthma attack (even for those not diagnosed with asthma). Symptoms  include:

• Heart: drop in blood pressure (anaphylactic shock), fainting,       chest pain, paleness


• Respiratory: swelling of the throat, hoarseness, choking,       difficulty breathing, coughing, wheezing


• Ear, nose and throat: mouth tingling, itching, swelling;       watery, red, itchy eyes; runny itchy nose, nasal congestion


• Abdomen: nausea, vomiting, diarrhea, abdominal cramps, uterine       cramps


• Skin: hives, flushing, itching, swelling


• Neurological: a sense of impending doom, anxiety, headache

Allergic reactions do not always present with skin symptoms;  most often they are multi-system, but can also present with only a single organ  system being affected?? (e.g., with only  severe airway constriction).

                       
                       

This post, Food Allergies: Treating Severe Allergic Reactions, was originally published on
                        Healthine.com by Paul Auerbach, M.D..