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Table 4 Differential Diagnosis of Anaphylaxis

From: World Allergy Organization Guidelines for the Assessment and Management of Anaphylaxis

Common diagnostic dilemmas Flush syndromes
   Acute asthmaa    Peri-menopause
   Syncope (faint)    Carcinoid syndrome
   Anxiety/panic attack    Autonomic epilepsy
   Acute generalized urticariaa    Medullary carcinoma of the thyroid
   Aspiration of a foreign body  
   Cardiovascular (myocardial infarctiona, pulmonary embolus) Nonorganic Disease
     Vocal cord dysfunction
   Neurologic events (seizure, cerebrovascular event)    Psychosomatic episode
Postprandial syndromes  
   Scombroidosisb Shock
   Pollen-food allergy syndromec    Hypovolemic
   Monosodium glutamate    Distributived
   Sulfites    Septic
   Food poisoning  
Excess endogenous histamine Other
   Mastocytosis/clonal mast cell disorderse    Nonallergic angioedema
   Basophilic leukemia Hereditary angioedema types I, II, & III
  ACE inhibitor-associated angioedema
     Systemic capillary leak syndrome
     Red man syndrome (vancomycin)
     Pheochromocytoma (paradoxical response)
  1. aAcute asthma symptoms, acute generalized urticaria, or myocardial infarction symptoms can also occur during an anaphylactic episode.
  2. bHistamine poisoning from fish, eg. tuna that has been stored at an elevated temperature; usually, more than one person eating the fish is affected.
  3. cPollen-food allergy syndrome (oral allergy syndrome) is elicited by fruits and vegetables containing various plant proteins that cross-react with airborne allergens. Typical symptoms include itching, tingling and angioedema of the lips, tongue, palate, throat, and ears after eating raw, but not cooked, fruits and vegetables.
  4. dDistributive shock may be due to anaphylaxis or to spinal cord injury.
  5. eIn mastocytosis and clonal mast cell disorders, there is an increased risk of anaphylaxis; also, anaphylaxis may be the first manifestation of the disease.
  6. Adapted from references [2, 2225, 31, 32, 91, 92].