“Separating Fact from Fiction in the Diagnosis and Management of Food Allergy”

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This great article/commentary is available as open access: Separating Fact from Fiction in the Diagnosis and Management of Food Allergy EM Abrams et al. J Pediatr 2022; 241: 221-228.

Key points:

  • “The risk of fatal anaphylaxis is about 1 in 10 million (about equivalent to being struck by lightning)..and fatality on first ingestion of an allergen in infancy has never been described”
  • Food allergy causes considerable morbidity/worsens quality of life (QOL): bullying, meal preparation, stress, social activities, and school attendance (with 10% choosing home schooling because of a food allergy). Some of this detriment on QOL is due to fear “that accidental exposure could result in fatal anaphylaxis”
  • “The impact of peanut allergy on QoL has been noted to be significantly worse than the impact of other chronic childhood diseases such as rheumatologic disease and type 1 diabetes mellitus”
  • Uriticaria does not equal allergy. “Although urticaria is commonly equated with a food allergy, food allergy accounts for less than 10% of the causes of all acute urticaria and is not a cause of chronic urticaria.” Urticaria can be triggered by an acute infection (most common etiology)
  • “Food proteins are digested within several hours; therefore, urticaria associated with a food ingestion will occur within minutes to 2 hours of ingestion, but typically last no more than a few hours (and less with treatment)” (an exception is meat anaphylaxis owing to galactose-α-1,3-galactose allergy)
  • Other common symptoms that are often incorrectly attributed to food allergy include headaches, chronic behavioral symptoms, or chronic nonspecific abdominal pain
  • Allergy testing: “the presence of a food-specific IgE is not itself indicative of an allergy…Although both skin prick testing and food-specific IgE testing are highly sensitive (>90% for skin prick tests, 70%-90% for sIgE), the specificity and positive predictive values of testing are often very low. The rate of false-positive tests is up to 40%.” 
  • Broad “panel testing” (eg, to a panel of “common” foods), or any food allergy diagnostic testing in the absence of a convincing clinical history has high potential to overdiagnose food allergy and result in unnecessary food avoidances
  • Don’t do IgG testing. “There is no evidence that IgG testing marks food sensitivity; in fact, the presence of IgG is both expected and is a potential indicator of ongoing tolerance”
  • For first-line management anaphylaxis, (intramuscular) epinephrine is the “only life-saving intervention available.” Antihistamines are useful only in the treatment of cutaneous symptoms/urticaria.
  • “Although oral corticosteroids are often administered in the setting of anaphylaxis, there is no convincing evidence that their use prevents a biphasic reaction…their routine use is not recommended” (for anaphylaxis)

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