Anaphylaxis 
 

Acute allergic reaction that have systemic manifestations including:

  1. Skin- flushing, pruritis, hives, angioedema of the eyelids, lips, and glottis.
  2. Gastrointestinal- nausea vomiting, diarrhea, abdominal pain
  3. Cardiovascular- hypotension, arrhythmia, syncope
  4. Respiratory- tearing or itching of eyes, swelling of lips, tongue, and upper airway structures, bronchospasm
Anaphylaxis results from the release of histamine from mast cells and basophils , prostaglandins, leukotrienes and other substances
  1. IgE mediated- there was a previous exposure, usually foods or drugs
  2. Complement system activation- often with blood products like IVIG
  3. Direct mast cell stimulation- contrast materials for xray examinations
  4. Unknown
The reaction may be immediate within seconds, delayed for hours, or be biphasic with recurrence of symptoms or new symptoms. There may be a prodrome such as a rash around the mouth, itchy tongue, lips, or mouth, that may cause the individual to seek attention prior to the development of more serious symptoms. At different times, patients will have a different reaction with the same contact. May be dose related.

Diagnosis

  1. Usually can make the diagnosis based on the history and physical symptoms and findings
  2. Lab evaluation of little benefit
  3. Common precipitators of anaphylactic reaction
    1. Foods
      1. Eggs, milk, soy- often outgrow
      2. Nuts, fish, shellfish
      3. Often there are cross reactivity among different foods within groups. It is advisable to avoid all nuts if you are allergic to peanuts unless oral challenges are negative. Avoidance is often difficult. Some foods are labeled under different names and may not be noticed. Also, certain foods have ingredients added that the patient is unaware of. This is especially common in baked goods that contain nuts.
      4. Additives are not common causes of anaphylaxis
    2. Stings- bees, wasps, fire ants. Must differentiate from localized reaction because if it is true anaphylaxis, immunotherapy may be indicated. 
    3. Pharmaceuticals
      1. Penicillin- most skin testing is ineffective because test material doesn't contain material that reaction is against. 
      2. Aspirin, NSAIDs, sulfonamides
      3. Vaccines-All vaccines have been reported to cause anaphylaxis but most discussion is about MMR because it is made with egg products and the high incidence of egg allergies in children. The MMR can be given to individuals sensitive to eggs if you watch them after the shot for 30 minutes and are prepared to give epinephrine. There is no reason to skin test first or give in small doses
      4. Contrast media
      5. Allergy shots- have patient wait after you give the shot to make sure there is no reaction
      6. IVIG
    4. Latex- common in spina bifida and patients with GU anomalies
    5. Exercise- different from exercise induced bronchospasm. May be sporadic and related to something the person ate prior to exercise. Food alone doesn't cause the reaction
    6. Idiopathic- recurrent anaphylaxis without apparent external cause
    Treatment
    1. Be prepared
    2. 1/1000 Epinephrine- 0.01ml/kg subcutaneously up to 0.3 ml. May repeat in q 15-20 minutes.
    3. Diphenyhydramine( Benadryl) Available over the counter in 12.5mg/5cc or 25mg/cap. May be given IM
    4. Steroids- up to 60mg
    5. If severe bronchospasm may give nebulized albuterol
    6. If stridor, may try epinephrine by nebulizer
    7. Careful observation after initiating treatment. Decision on admitting child to hospital is dependent on condition after therapy.
    8. Child should have Medic-Alert bracelet
    9. Family, school, camp, baby-sitter, etc. should be aware of the condition and know what to avoid. Also they should be familiar with reaction and have an Epinephrine 'kit" available and know how to use it. 
    References
    1. Freeman TM. Anaphylaxis: Diagnosis and Treatment. Primary Care; Clinics in Office Practice. 1998; 25(4):809-817.
    2. Goldstein, H. Drug Sensitivity. Pediatrics in Review. 1998; 19:33. 
    3. Wood RA Anaphylaxis: Causes and Management. Contemporary Pediatrics July 1996 89-105 
    4. Donley DR. Pediatric Anaphylaxis, Insect Stings, and Bites.  Immunology, Allergy Clinics of North America.  May 1999; 19 (2) 347-361
    5. Sampson, Hugh  Peanut Allergy. NEJM Vol 346(17) pp1294-99 April 25, 2002
    6. Leung D. et al. Effect of Anti-IgE Therapy in Patients with Peanut Allergy. NEJM 348:11 pg986 March 13, 2003
    7. Lack G et al. Factors Associated with the Development of Peanut Allergy in Childhood. NEJM Vol 348:11 pg 977 March 13, 2003
    8. Metzger H Two Approaches to Peanut Allergy NEJM Editorial March 13, 2003
    9. Sampson Hugh. Anaphylaxis and Emergency Treatment. Pedatrics Supplement June 2003
    10. Pichichero M. A Review of Evidence Supporting the American Academy of Pediatrics Recommendation for Prescribing Cephalosporin Antibiotics for Pencillin-Allergic Patients. Pediatrics April 2005 pg 1048
    11. Gruchalla R. Pirmohamed M. Antibiotic Allergy NEJM Feb 9, 2006
    12. Lieberman P. Kemp S. etal. The diagnosis and management of anaphylaxis: an updated practice parameter.  J Allergy Clin Immunol 2005 Suppl: S 483