Fawzya abo aliProf. of int.medicine & allergyAin shams faculty of medicine
Emily’s StoryEmily Vonder MeulenBorn 1992 Eczema immediatelypresent on much of herbody Peanut Allergy at 2 yearsold Diagnosed with Asthmaaround 10 years oldwww.foodallergyangel.com
April 2006, one month from 8thgrade graduation and from her 14thbirthdayshe went shopping for graduation dress Emily was at a Cincinnati restaurantwhere she ordered a chicken sandwich. Catrina,the mother said ,we orderedaround 2:50and were done eating about3:10 But, about 10 minutes after shefinished it, she struggled to breathe.I called 911 at 3:26 but it was toolate.The doctor’s pronounced her dead at4:20 from anaphylaxis.
What is food allergy?What is food allergy? Food allergy is one of the adversereactions to food ,defined as: anabnormal response to food, mediatedvia the immune system.
Epidemiology: Approximately 8% of children and 1-6% of adultssuffer from true food allergies.
Pathophysiology GI tract forms a barrier to outside environment GALT inhibits responses to non-dangerous antigenswhile mounting responses to pathogens Intact food antigens may penetrate the GI tract butnot cause clinical symptoms Develop in genetically predisposed individuals whenoral tolerance fails Increased intestinal permeability to macromolecules ; – Viral gastroenteritis, premature birth, cystic fibrosis – Leaky gut syndrome (LGS)
Foundation for Integrated MedicineImmunologic Mechanisms ofFood allergy Type I (IgE mediated, TH2 promoted) Type II (IgG and complement mediated,cytotoxic, TH1 promoted) Type III (IgG immune complex mediated,TH1 promoted) Type IV (cell-mediated, TH1 promoted)
Non-IgE MediatedType II: Antibody dependent cytotoxicity Specific antibody binds to a surface tissueantigen and Milk-induced thrombocytopeniaType III: Antigen-antibody complex mediated Can be found in sera of normal patients&in patients with food hypersensitivity Little support for causing disease
Type IV: Cell-mediated hypersensitivityMediated by sensitized CD4+ T lymphocyteswhich process antigens and release cytokines . the reaction mediated through macrophagesbegins in hrs but reaching a peak in 2 to 3 days.
Fatal Food-Induced AnaphylaxisAccounts for 1/3 of all anaphylaxis seen inemergency rooms Symptoms:generalized Dx by history and demonstration of food specific IgE Most were adolescents or young adults History of prior reaction to implicated food Only 10% had epinephrine available Peanuts and tree nuts for majority (94%)
Exercise-Induced Anaphylaxis (EIA) Rare form occurring when patientexercises 2-4 hrs after ingestion ofspecific food Without exercise, food no problem Most common in women prior tomenstruation Dx based on history and evidence ofspecific IgE Common offenders: wheat, shellfish,fish, fruits, milk
Treatment of food allergy Treat the reaction Avoid the food:The only proven treatmentfor a food allergy is to avoid the food. Read food labels OIT and SLIT show great promise, and awidespread treatment for food allergy maybe within reach. probiotics