IgE mediated food allergy

Prevalence:

• Up to 20% of people report food-related symptoms.
• True food allergy prevalence is estimated at 1–3%, higher in children.

Pattern of Food Allergies:

• Egg and milk allergies common in young children but often outgrown.
• Peanut, tree nut, and shellfish allergies develop later and tend to persist.

Food Anaphylaxis:

• Represents 30% of fatal anaphylaxis and 17% of anaphylaxis presentations to emergency departments.
• Peanut and tree nut allergies cause most fatalities; milk, fish, and seafood also contribute.

Recognition and Management:

• Early treatment is crucial due to unpredictable progression from itching to urticaria to death.
• Anaphylaxis may present with hypotension alone or acute diarrhea.
• Patients with severe reactions to insect stings should be prescribed an adrenaline autoinjector and referred for testing and immunotherapy.

Treatment Considerations:

• Anaphylaxis in patients on beta blockers may require IV glucagon.
• Prepare for vomiting when using glucagon.
• Protracted anaphylaxis may require extensive treatment, including fluid resuscitation and vasopressors.

Diagnosis:

• Serum tryptase assay is specific for anaphylaxis but a negative result does not exclude it.

Long-term Management:

• Most children develop tolerance to common allergens (egg, milk, wheat, soy) by 5–6 years.
• Periodic re-evaluation and supervised oral food challenges recommended.
• Peanut and tree nut allergies often persist into adulthood in up to 80% of cases.

Inadvertent Exposures:

• even with careful attention to allergen avoidance approximately 14% of children will have an inadvertent exposure to their food allergen within 1 year.
• Higher risk in young adults/adolescents due to less careful label reading and risk-taking behavior.
  • increased risk taking behaviour
  • increasing desire for independence
  • peer pressure
  • less parental supervision
  • poor appreciation of the danger.

Risk Factors for Fatal Food Anaphylaxis:

• Peanut or tree nut allergy.
• Adolescence or young adulthood.
• Eating away from home.
• Having asthma, with most fatalities occurring in asthmatics.
  • the vast majority of fatalities from food anaphylaxis (75–98%) occur in asthmatics, which suggests that optimal asthma control is another important management aim.

Preventive Measures:

• Optimal asthma control is crucial for reducing risk.
• Awareness of high-risk situations (restaurants, social gatherings) is important.