Allergic Disorders PDF

ALLERGIC DISORDERS DR. ALISON HAYNES, MD, FRCPC, MPH  OBJECTIVES 8052 identify mechanisms of allergic reactions, i.e., immediate and delayed hypersensitivity reactions 8057 differentiate between food allergy and food intolerance 8058 recognize signs / symptoms and man...

ALLERGIC DISORDERS DR. ALISON HAYNES, MD, FRCPC, MPH  OBJECTIVES 8052 identify mechanisms of allergic reactions, i.e., immediate and delayed hypersensitivity reactions 8057 differentiate between food allergy and food intolerance 8058 recognize signs / symptoms and management of anaphylaxis 9197 describe the pathophysiology of anaphylaxis 9198 identify the signs and symptoms of food allergies 9199 list investigations for IgE mediated and non-IgE mediated food allergies 9200 discuss the long-term management of food allergies Atopic Dermatitis Food Allergy Asthma Allergic Rhinitis  RISK FACTORS 20% general population has an allergic disorder Family history is the strongest predictive factor 30 – 50% if one 1st degree relative with an allergic disorder 75% if two 1st degree relatives with an allergic disorder  CASE #1 6-month-old presents to the ER Diffuse urticaria Wheeze on auscultated Vitals stable Had cow’s milk protein 15 minutes before onset of symptoms  ADVERSE FOOD REACTIONS NON IMMUNE MEDIATED IMMUNE MEDIATED METABOLIC PHARMACOLOGIC TOXIC IGE NON IGE MIXED Lactose Caffeine Food Anaphylaxis Food protein Eosinophilic intolerance poisoning induced esophagitis enterocolitis syndrome IgE mediated reaction = Immediate hypersensitivity reactions Non IgE mediated reactions = Delayed hypersensitivity reactions  IGE MEDIATED FOOD REACTIONS 6 – 8% of children, 3 – 4% of adults have food allergy Detailed history is essential Food suspected? Details of exposure to food during reaction? Specific symptoms? Timing of symptoms? Reproducibility of reactions? IGE MEDIATED FOOD REACTIONS  IGE MEDIATED FOOD REACTIONS Details of exposure Previous exposure to foods? Route of exposure (e.g., ingestion, contact, inhaled)?  IGE MEDIATED FOOD REACTIONS Specific symptoms: cutaneous Urticaria and angioedema are most common symptoms  IGE MEDIATED FOOD REACTIONS Specific symptoms: respiratory Rhinorrhea Cough Wheeze Shortness of breath  IGE MEDIATED FOOD REACTIONS Specific symptoms: gastrointestinal Nausea Abdominal pain Vomiting Diarrhea  IGE MEDIATED FOOD REACTIONS Specific symptoms: cardiovascular Fainting Hypotension  IGE MEDIATED FOOD REACTIONS Timing of reaction Typically beginning within minutes to two hours from the time of exposure Resolved within a few hours Reproducibility Reaction with each subsequent exposure to the food  CASE # 1 Foods suspected: cow’s milk protein Details of exposure: cow’s milk protein formula Specific symptoms: urticaria and wheeze Timing of symptoms: 15 minutes after ingestion Reproducibility of reactions: same reaction with previous exposure to cow’s milk protein  CASE # 1 6-month-old presents to the ER Hives Wheeze Diagnosed with anaphylaxis Serious life-threatening reaction from exposure to an allergen  MANAGEMENT Discontinue / remove the allergen  MANAGEMENT Epinephrine intramuscular injection Intravenous fluids Antihistamines ONLY help with hives CPS Statement: Emergency treatment of anaphylaxis in infants and children  EPINEPHRINE AUTO-INJECTOR All patients should be discharged with an epinephrine auto-injector Auto-injectors available EpiPen® 0.3mg / EpiPen Junior® 0.15mg Allerject ® 0.3mg / Allerject ® Junior 0.15mg Emerade ® 0.3mg / Emerade ® 0.5mg Dose 0.15mg device all patients up to 25kg 0.30mg device patients over 25kg  TRIGGER AVOIDANCE 1/3 presenting to the ER have an identifiable trigger  ALLERGY REFERRAL History is the most important tool!!  SKIN PRICK TESTING Solutions containing proteins placed on skin Food, aeroallergens, venom, medications Localized hive develops if patient is sensitized SERUM SPECIFIC IGE IGE MEDIATED FOOD REACTIONS Management Food avoidance Epinephrine auto-injector Anaphylaxis action plan Medical identification device  CASE # 2 7-month-old referred to the allergy clinic for suspected food allergy  CASE # 2 Foods suspected: oats Details of exposure: ate 3 spoon fulls of oat cereal Specific symptoms: profuse vomiting and lethargy Timing of symptoms: 3 hours after ingestion Reproducibility of reactions: same reaction with ingestion of oat cereal two previous times  NON IGE MEDIATED FOOD ALLERGY Immunologic food reaction that is likely T cell mediated Symptoms are typically isolated to the gastrointestinal tract Proctitis is inflammation in the rectum Enterocolitis is inflammation in small and large intestines FOOD PROTEIN INDUCED PROCTITIS Exclusively breastfed infants aged 2 - 8 weeks old Transfer of food proteins ingested by the mother to the infant through breastmilk Cow’s milk protein, egg, soy, corn Blood-tinged stools, otherwise healthy Skin testing and serum specific IgE NOT helpful  FOOD PROTEIN INDUCED ENTEROCOLOTIS SYNDROME Onset 1 - 4 weeks after introduction of the food Cow’s milk protein, soy, grains, rice, meat / poultry, egg, potato, legumes Repetitive vomiting 1- 3 hours after ingestion Skin testing and serum specific IgE NOT helpful  CASE # 2 Diagnosed with oat induced enterocolitis syndrome based on history Remove oats from the diet  CASE #3 17-year-old referred to the allergy clinic for suspected food allergy  CASE #3 Foods suspected: cow’s milk protein foods Details of exposure: symptoms with large amounts of cow’s milk protein, tolerates smaller amounts Specific symptoms: diarrhea, cramping, bloating Timing of symptoms: 30 minutes Reproducibility of reactions: same reaction with ingestion of yogurt and cheese  LACTOSE INTOLERANCE Non immune mediated food reaction Caused by low levels of the enzyme lactase in small intestine Present with diarrhea, abdominal pain, bloating  CASE # 3 Patient diagnosed with lactose intolerance Consumes lactose free products  SUMMARY Food reactions are divided into immune mediated (IgE, non IgE) and non immune mediated IgE mediated food reactions present with cutaneous, respiratory, gastrointestinal and cardiovascular symptoms within mins - 2 hours Non IgE mediated reactions present after at least 1 hour of exposure and mostly involve gastrointestinal symptoms Anaphylaxis is a life-threatening condition that requires prompt treatment with epinephrine QUESTIONS? 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