Allergy Capital

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Anaphylaxis

Anaphylaxis is a medical emergency. As the most severe form of allergy, symptoms include life-threatening breathing difficulty, hives, stomach upset or shock. Use of injected adrenaline (epinephrine) should be considered as First Aid.

What is anaphylaxis?
Anaphylaxis is the most severe form of allergic reaction. It results in potentially life-threatening symptoms such as difficulty breathing, hives, stomach upset or a drop in blood pressure (shock). Other symptoms include swelling of the face or throat, dizziness, difficulty thinking, an intense sense of fear, tightness in the chest, vomiting or diarrhoea. Use of injected adrenaline (epinephrine) should be considered as First Aid.

Common causes of Anaphylaxis

• Food Allergy: Most commonly nuts, seeds, fish and crustaceans in adults; cows milk, soy, egg, nuts, and wheat in young children
• Medication (drug allergy): Particularly painkillers and antibiotics
• Insect stings(venom allergy) such as bee, wasp, "jumper ants".
• Exercise (either alone or in combination with food allergy)
• Idiopathic. When a cause cannot be identified, cases are called "idiopathic".
• Tick bites
• Latex allergy
• Herbal remedies (e.g. Echinacea, Royal Jelly)
• Cold urticaria. Some patients who get hives when exposed to cold air or water, or go into shock if they swim in cold water.

How is anaphylaxis managed?
People who have had an episode of anaphylaxis need to:

• Identify and avoid the cause (if possible)
• Develop avoidance strategies
• Wear a MedicAlert bracelet identifying your allergy & its treatment
• Recognize the early symptoms of an allergic reaction
• Know what to do if it happens again
  

Identifying the cause
Your doctor will normally ask a series of questions that may help to narrow down the list of likely causes such as foods or medicines consumed that day, or exposure to stinging insects. Anaphylaxis usually occurs within minutes of a sting, and within hours of a food allergen or drug. That means that the history of everything eaten or drunk in the previous 12 hours is of utmost importance. This approach will also help to exclude conditions that can sometimes be confused with anaphylaxis. Skin or blood (RAST) allergy testing help confirm or exclude potential triggers.

What determines the severity of a reaction ?

• The severity of the allergy.
• The amount of food eaten (more food=more severe)
• The form of the food (e.g. liquid may be absorbed faster, resulting in more severe & rapid reactions)
• Whether it is eaten on its own or mixed in with other foods (e.g. scrambled egg may cause immediate facial swelling, but that in cake may be more slowly absorbed and result in delayed reactions)
• Exercise around the same time as the meal may worsen severity. Some patients will only react to a food if they exercise around the same time, a condition called food and exercise-induced anaphylaxis. In these circumstances, the severity of the reaction is usually determined by the amount of food eaten, the vigor of the exercise and the time between the two.
• Cooking of the food may alter the structure of the food allergen and make it less likely to provoke severe reactions (sometimes seen with egg and milk, but rarely with nuts or seafood)
• Other factors (such as hot days, alcohol with the meal, pain killers or infection)
  

Recognizing the symptoms
Early symptoms of an allergic reactions often include an itchy mouth, hands or feet, followed by the more devastating symptoms previously described. Other symptoms include red, itchy and puffy eyes, and hives that start around the armpits and groin (see photos below). These should be considered as warning signals to get emergency medical help and to start treatment immediately until help arrives.

Develop an Emergency Action Plan
A well thought-out "Action Plan" is an essential part of management and should be practiced. It requires you to recognize early warning symptoms, to carry the medication you need and to know how to use it.

• Remove the trigger & minimize the effect of co-factors (e.g. spit out the offending food to minimize further absorption of allergen, stop exercising).
• Seek urgent medical assistance (e.g. call an ambulance)
• Inject adrenaline (epinephrine). Injected adrenalin works rapidly to reverse the effects of anaphylaxis and should be considered "First Aid" for its treatment.
• Other medication. Some patients will be advised to take other medicines like antihistamines or cortisone tablets. It is important to realize that these will not prevent a life-threatening allergic reaction, as they take the best part of an hour to be absorbed.
• Observe for relapse under medical supervision. This is because severe symptoms ("rebound") sometimes recur after apparent recovery.

School children are particularly at risk, and an Emergency Action Plan also needs to be developed for use in this situation.

Psychological issues
Anaphylaxis is a disorder where the threat of recurrence persists but the event itself (and its severity), unpredictable. Some patients (or their parents) will suffer considerable stress and anxiety. Review by your doctor after each relapse offers an opportunity to review appropriate management strategies including the correct use of EpiPen, to ensure that the device is renewed at appropriate intervals and to provide counselling where appropriate.

Other management issues

• Patients who have had anaphylaxis should wear a Medic Alert bracelet. This increases the likelihood that adrenalin will be administered in an emergency.
• Some types of heart and blood pressure medicines (such as Beta-blockers or ACE inhibitors) can make anaphylaxis worse, or interfere with the drugs used in treatment. These are best avoided.
• Immunotherapy (desensitization) injections are only useful for anaphylaxis caused by bee or wasp stings, but not for treating severe food allergy.
• Patients who go bushwalking to isolated areas should consider carrying an emergency satellite beacon to call for assistance if an emergency arises

Emergency satellite beacon

Who should carry adrenaline (epinephrine)?
Food allergy in infancy is common (around 1 in 20 have at least a transient food allergy). While it is natural to be anxious about having another allergic reaction, serious allergic reactions fortunately occur much less often. Patients are usually advised to carry adrenaline (epinephrine) when they are considered to be at significant risk of having further dangerous allergic reactions. Factors that may be considered when reaching this decision may include:

• Dangerous allergic reactions in the past
• Frequent asthma requiring regular medication
• Living remote from medical care (eg. on a farm a long way from hospital)
• Other factors (eg. frequent travel)
  

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Web Links to Additional Information on Food Allergy, Stinging Insect Allergy & Anaphylaxis

PATIENT SUPPORT GROUPS	Food Allergy Network (USA)
	FACTS (Food Anaphylaxis in Children, Training and Support, Australia)
	The Anaphylaxis Campaign (UK)
	Peanut Allergy Site (USA)
PROFESSIONAL MEDICAL SITES	ASCIA Education Resources (Australasian Society of Clinical Immunology & Allergy)
	National Jewish & Medical Research Center (Anaphylaxis Section; USA)
	Canadian Information Handbook on Anaphylactic Shock (downloadable pdf file; Canada)
	Food Allergy Site (Switzerland)
POSITION STATEMENTS	Guidelines for the prevention, recognition and management of anaphylaxis in child care and school sites. A Position Statement of the Australasian Society for Clinical Immunology and Allergy (ASCIA) (web link to this ASCIA document)
	Anaphylaxis in schools and other child-care settings. Position Statement of the American Academy of Allergy, Asthma and Clinical Immunology (AAAAI) (web link to this document)
	The Use of Epinephrine in the Treatment of Anaphylaxis. Position Statement of the American Academy of Allergy, Asthma and Clinical Immunology (web link to this document)
EDUCATIONAL ARTICLES	Tips to Remember: Food Allergy (AAAAI) (web link to this information)
	Tips to Remember: Stinging insect allergy (AAAAI) (web link to this information)
	Anaphylaxis (Australasian Society for Clinical Immunology and Allergy) (web link to this information)
	Tips to Remember: What is anaphylaxis? (AAAAI) (web link to this information)

PROFESSIONAL ARTICLES	Stinging Insect Allergy (web link to MJA article)
	Prof M Fisher. Treatment of Anaphylaxis (web link to BMJ article)
	Ewan PW. ABC of Allergies: Anaphylaxis. BMJ 1998; 316: 1442-45.(Web link to BMJ article)
	Administration of medicines in school: who is responsible? BMJ 1998; 316: 1591-3. (web link)
	Australian Venom Research Unit, University of Melbourne

COMMERCIAL SITES (information provided but not necessarily endorsed by this web site)	Allergypack Web site selling "Pen Pals" for carrying Epipen devices (web link)
	Protectube Web site selling a protective carrying case for Epipen (web link)

References

• Shadick NA et al. The natural history of exercise-induced anaphylaxis: survey results from a 10 year follow-up study. J Allergy Clin Immunol 1999; 104: 123-7.
• Joint Committee on Allergy, Asthma and Immunology. Practice Parameters: The Investigation and Management of Anaphylaxis. Journal of Allergy and Clinical Immunology 1998; 101 (6): S465-528.
• Bochner BS, Lichenstein LM. Anaphylaxis. N Eng J Med 1991; 324: 1785-90.
• Atkinson TP, Kaliner MA. Anaphylaxis. Med Clin N America 1992; 76: 841-55.
• Sheffer AL, Austen FK. Exercise-induced anaphylaxis. J Allergy Clin Immunol 1983; 66: 106-11.
• Ditto AM et al. Idiopathic anaphylaxis: a series of 335 cases. Ann Allergy Astham Immunol 1996; 77: 285-91.
• Weiler JM. Anaphylaxis in the general population: a frequent and occasionally fatal disorder that is underrecognised. J Allergy Clin Immunol 1999; 104:
• Clinical and Laboratory Practice Committee Position Statement. Guidelines for the prevention, recognition and management of anaphylaxis in child care and school sites. Australasian Society for Clinical Immunology and Allergy. ASCIA Newsletter March/April 1998: 6-9.
• Guidelines for urgent care in schools. Committee on School Health, American Academy of Pediatrics. Pediatrics 1990; 86: 999-1000.
• American Academy of Pediatrics, Section on Allergy and Immunology. Anaphylaxis at school: etiological factors, prevalence and treatment. Pediatrics 1993; 91: 516.
• AAAAI Board of Directors. The use of epinephrine in the treatment of anaphylaxis. Journal of Allergy and Clinical Immunology 1994; 94: 666-668.
• Bannon MJ, Ross EM. Administration of medicines in school: who is responsible ? Brit Med J 1998; 316: 1591-3.
• Guinnepain M-T et al. Exercise-induced anaphylaxis: useful screening of food sensitization. Ann Allergy Asthma Immunol 1996; 77: 491-6.
• Van der Klauw MM et al. Drug-associated anaphylaxis: 20 years of reporting in the Netherlands (1974-94) and review of the literature. Clin Exp Allergy 1996; 26: 1355-63.
• DeShazo RD et al. Allergic reactions to drugs and biological agents. JAMA 1997; 278: 1895-906.

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