Anaphylaxis — Clinical Criteria for Diagnosing Anaphylaxis — Clinical Pathway: Emergency

Anaphylaxis Clinical Pathway — Emergency Department

Child with Suspected Anaphylaxis

Clinical Criteria For Diagnosing Anaphylaxis

Anaphylaxis is highly likely when ONE of the following 3 criteria are fulfilled within minutes to 2-3 hours following possible allergen exposure
CRITERIA 1

Acute onset of an illness with involvement of the skin, mucosal tissue, or both
(e.g., generalized hives, pruritis or flushing, swollen lip-tongue-uvula)

AND AT LEAST ONE OF THE FOLLOWING

  • Respiratory compromise
  • Reduced BP or associated symptoms of end-organ dysfunction
  • Persistent GI Symptoms, Significant abdominal pain and/or significant vomiting
CRITERIA 2

Two or more of the following that occur rapidly after exposure to a LIKELY ALLERGEN for that patient:

  • Involvement of the skin-mucosal tissue
  • Respiratory compromise
  • Reduced BP or associated symptoms
  • Persistent gastrointestinal symptoms
CRITERIA 3 Reduced BP after exposure to KNOWN ALLERGEN for that patient

Anaphylaxis Caveats

  • A patient who presents with hypotension alone after exposure to known allergen meets anaphylaxis criteria.
  • While the majority of anaphylaxis cases involve skin symptoms, 10% of patients do not have hives or other skin manifestations; these patients often have the most severe symptoms.
  • Isolated skin findings alone (generalized hives) should not automatically be defined as anaphylaxis.
  • In a patient with exposure to a known allergen that has previously caused anaphylaxis that presented with hives alone, threshold should be low for the diagnosis of anaphylaxis.
  • The above signs/symptoms obviously can be due to non-allergic causes.
  • The absence of exposure to a known allergen should never preclude the diagnosis of anaphylaxis.
  • Patients on beta blockers should get glucagon if the first dose of epinephrine is ineffective.

Examples of Anaphylaxis

  • Patient with history of peanut allergy presents with acute onset of generalized hives and wheezing after possible or known exposure to peanut.
  • Patient with history of milk allergy presents with acute onset of lip/tongue swelling and vomiting after possible or known exposure to milk.
  • Patient with history of shellfish allergy presents with acute onset of persistent cough, rhinorrhea, and crampy abdominal pain after possible or known exposure to shellfish.
  • Patient with no history of allergies presents with acute onset of hives, wheezing, and vomiting soon after eating peanuts.
  • Patient with history of tree nut allergy presents with acute onset hypotension after accidentally eating almonds.