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Food hypersensitivity


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Food hypersensitivity

  1. 1. Food Allergy Prof. Dr. Saad S Al Ani Senior Pediatric Consultant Head of Pediatric Department Khorfakkan Hospital Sharjah ,UAE [email_address]
  2. 2. Epidemiology <ul><li>5% - 8% in pediatric population </li></ul><ul><li>Most common allergens in children: </li></ul><ul><li>□ Milk </li></ul><ul><li>□ Eggs </li></ul><ul><li>□ Peanuts </li></ul><ul><li>□ Tree nuts </li></ul><ul><li>□ Soy </li></ul><ul><li>□ Wheat </li></ul>Jason W.C. the Harriet lane Handbook.8 th ed.p:388.Mosby.2009
  3. 4.   Nature of symptoms with immune ( allergy ) and non - immune hypersensitivity reactions ( intolerance)
  4. 6. Manifestations Often a combination of several syndromes 1.Anaphylaxis 2.Skin syndromes 3.Gastroentistinal syndromes 4.Respiratory syndromes
  5. 7. 1.Anaphylaxis <ul><li>Risk factors for fatal outcome: </li></ul><ul><li>1.History of asthma </li></ul><ul><li>2.Peanut or tree nut allergy </li></ul><ul><li>3.Delayed administration of epinephrine </li></ul>Uniphasic , Biphasic, or Protracted patterns
  6. 8. 2.Skin Syndromes A. Urticaria / Angioedema : 1.Chronic Urticaria rarely related to food allergy 2.Acute urticaria predicts risk for future anaphylaxis
  7. 9. Cont. <ul><li>B. Atopic Dermatitis / eczema </li></ul>1. Food allergy more common in patients with atopic dermatitis 2. Acute and chronic skin changes often coexist
  8. 11. 3.Gastrointestinal Syndromes <ul><li>Oral allergy syndrome </li></ul>1- Edema of oral mucosa after ingestion of certain fresh fruits and vegetables in patients with pollen allergies 2 - Inciting antigens destroyed by cooking 3 - Caused by cross-reactivity of antibodies to pollens 4 - Rarely progresses beyond the mouth
  9. 12. Cont. <ul><li>B. Allergic Eosinophilic Gastroenteritis , Esophagitis </li></ul>1- Reflux ,abdominal pain ,diarrhea ,early satiety 2 – characterized by eosinophilic infiltration of digestive tract
  10. 13. Cont. <ul><li>C. Food –induced Enterocolitis </li></ul>1- Presents in infancy 2 – vomiting and diarrhea (may contain blood ) when severe may lead to : Lethargy ,Dehydration ,Hypotension ,Acidosis 3 – Most commonly associated with milk ,soy
  11. 14. Cont. <ul><li>D. Infantile Proctocolitis </li></ul>1- Confined to distal colon and presents with only diarrhea 2 – Symptoms of short duration ,rarely leads to anemia
  12. 15. 4.Respiratory syndromes <ul><li>C. Heiner syndrome </li></ul>A. Rhinitis B. Asthma
  13. 16. Heiner syndrome <ul><li>Features: </li></ul><ul><li>- Pulmonary infiltrate </li></ul><ul><li>- Hemosiderosis </li></ul><ul><li>- Anemia </li></ul><ul><li>- Recurrent pneumonia </li></ul><ul><li>- Failure to thrive </li></ul>Precipitating IgG antibody to cow’s milk
  14. 17. Diagnosis Food allergy is suspected when typical symptoms occur with the introduction of specific foods. 2.Pharmacologic activity of foods Other non-allergic mechanisms of food intolerance should be ruled out: 1.Compromised digestive or absorptive processes 3.Contamination with microbes or toxins
  15. 18. Cont. <ul><li>Lactose intolerance should be considered when cow's milk allergy is suspected. </li></ul><ul><li>Elimination diet and subsequent double-blind, placebo-controlled food challenge (DBPCFC) are the gold standard for diagnosis of food allergy. </li></ul>
  16. 19. Cont. <ul><li>In DBPCFC , suspected foods are administered in capsules in progressively increasing amounts, alternating with placebo, and reactions are evaluated in a blinded fashion. </li></ul><ul><li>Open food challenges , although commonly performed, are less reliable (except in young infants). </li></ul>
  17. 20. Cont. <ul><li>When anaphylaxis has followed ingestion of a food , challenge should not be performed , and an allergist should evaluate the child . </li></ul><ul><li>Symptoms can be reproduced by DBPCFC in only 40% of children with suspected food allergy </li></ul>
  18. 21. Cont. <ul><li>The judicious use of a skin prick </li></ul><ul><li>test or radioallergosorbent test ( RAST ) </li></ul><ul><li>can be very useful in determining whether </li></ul><ul><li>an IgE allergic reaction is the cause of a </li></ul><ul><li>food allergy. </li></ul><ul><li>Children can be tested for IgE reactions to foods at any age because IgE is made by 24 wk gestation . </li></ul>
  19. 22. Cont. <ul><li>A negative IgE test , especially if the </li></ul><ul><li>patient is older than 1 yr of age , is very </li></ul><ul><li>accurate in predicting that the reaction </li></ul><ul><li>is not IgE mediated . </li></ul><ul><li>The significance of a positive </li></ul><ul><li>IgE test has to be determined </li></ul><ul><li>by the history and the age of the patient. </li></ul>
  20. 23. Cont. <ul><li>Total-serum IgE is unreliable in diagnosing food allergy. </li></ul><ul><li>A positive skin test is found in nearly 100% of children 3yr of age or older who have a positive DBPCFC. </li></ul>
  21. 24. Cont. <ul><li>In infancy , hypersensitivity is most often associated with ingestion of cow's milk or soy protein . </li></ul>Among infants and children with food allergy , 90% of reactions are to egg , milk , peanuts , soy , and wheat
  22. 25. Cont. <ul><li>Seventy-five per cent of children with food allergy react only to a single food. </li></ul><ul><li>Children with allergic eosinophilic gastroenteritis are the exception, often reacting to multiple foods </li></ul>
  23. 26. Treatment and Prognosis. The only therapy proved effective for food allergy is an elimination diet . Most gastrointestinal manifestations resolve within several days , although some may take weeks (food-induced enteropathy ).
  24. 27. Cont. <ul><li>A child at risk for a severe and life-threatening IgE-mediated reaction should have access to injectable epinephrine and an antihistamine. </li></ul>At least 30% of infants with cow's milk allergy also demonstrate sensitivity to soy protein.
  25. 28. Cont. <ul><li>These infants improve with protein hydrolysate </li></ul><ul><li>formula; </li></ul><ul><li>less than 5% have persistent symptoms and </li></ul><ul><li>these cases resolve with the use of amino acid- </li></ul><ul><li>based formulas. </li></ul><ul><li>Re-lactation is an alternative when cow's milk allergy presents early . </li></ul>
  26. 29. Cont. About 50% of infants who experience proctocolitis while nursing improve with removal of cow's milk from the mother's diet. If the symptoms are severe enough (anemia and hypoproteinemia) decide to change in the infant's diet to a protein hydrolysate formula.
  27. 30. Cont. <ul><li>Eighty-five per cent of infants with non-IgE-mediated food hypersensitivity to milk proteins no longer have symptoms on food challenge by 3 yr of age. </li></ul>Resolution of symptoms from cow's milk or soy protein hypersensitivity is common by 1 yr of age .
  28. 31. Cont. When milk is reintroduced, only a teaspoon or less should be offered at first and then increased progressively over a few days if tolerated Even older children and adults may lose their sensitivity to an offending food when it is eliminated from the diet for 1 to 2 yr
  29. 32. Cont. <ul><li>Symptoms from IgE-mediated allergy to peanut, nuts, fish, or shellfish are the exception and do not resolve. </li></ul>
  30. 33. References <ul><li>Jeffrey Hyams . Food Allergy (Food Hypersensitivity) .in Nelson textbook of pediatrics(19 th ed)chap318 </li></ul><ul><li>Kokkonem J, Haapalabit M, Laurila K, et al: Cow's milk protein-sensitive enteropathy at school age. J Pediatr 2001;139:797-803. </li></ul><ul><li>Sampson HA, Anderson JA: Summary and recommendations: Classification of gastrointestinal manifestations due to immunologic reactions to foods in infants and young children. J Pediatr Gastroenterol Nutr 2000;30:S87 </li></ul><ul><li>Sicherer SH, Noone SA, Koerner CB, et al: Hypoallergenicity and efficacy of an amino acid-based formula in children with cow's milk and multiple food hypersensitivities. J Pediatr 2001;138:688 </li></ul><ul><li>Sicherer SH: Food protein-induced enterocolitis syndrome: Clinical perspective. J Pediatr Gastroenterol Nutr 2000;30:S45. </li></ul>
  31. 34. Thank you