7.food allergy
Post on 12-May-2017
223 Views
Preview:
TRANSCRIPT
May 21, 2007 smt vi lecture, foodallergy 1
Food allergy
Dewi KumaraChild Health Dept
May 21, 2007 smt vi lecture, foodallergy 2
Definition a group of disorders distinguished by the
way the body's immune system responds to specific food proteins.
Most by type I hypersensitivity reaction
May 21, 2007 smt vi lecture, foodallergy 3
Adverse reaction to food General terminology toward unwanted
reaction to food. Maybe secondary to food allergy or intolerance to food
May 21, 2007 smt vi lecture, foodallergy 4
Food intolerance Is a non immunological reaction The most common cause of adverse reaction to
food. Maybe caused by toxic contaminant ( histamine in
scromboid fish, toxin secreted by salmonella, shigella, camphylobacter)
Pharmacologic (cafein in coffee, tyramine in cheese)
Genetic: metabolism disorder( lactase/maltase deficiency)
May 21, 2007 smt vi lecture, foodallergy 5
Adverse reaction to food
Immunologic Non immunologic
Toxic
pharmacologic
metabolism
Type IHypersensitivity
Other typehypersensitivity
May 21, 2007 smt vi lecture, foodallergy 6
Some children may also be intolerant of food colorings, additives, and preservatives. Among these are yellow dye number 5, which can cause hives; and monosodium glutamate, which produces flushing, headaches, and chest pain. Sulfites, another additive, have been found to cause asthmatic reactions and even anaphylactoid reactions. Sulfites are preservatives used in wines, maraschino cherries, seafood, and soft drinks. They are sometimes put on fresh fruits and lettuce to maintain their fresh appearance, on red meats to prevent brown discoloration, and even in prepared deli foods like crab salad. Sulfites appear on food labels as sodium sulfite, sodium bisulfite, potassium bisulfite, sulfur dioxide, and potassium metabisulfite. The U.S. Food and Drug Administration (FDA) has banned the use of sulfites as a preservative for fruits and vegetables, but they are still in use in some foods.
May 21, 2007 smt vi lecture, foodallergy 7
Statistics:
Eight percent of children < 6 years experience food intolerances. Of this group, 2 to 4%: allergic reactions to food.
Peanut and/or tree nut (e.g. walnut, almond and cashew) allergy affects about three million Americans, or 1.1% of the population.
In US, 150 die / year from food-related anaphylaxis. .
May 21, 2007 smt vi lecture, foodallergy 8
Etiology of food allergyChildren Adultmilk peanutsegg tree nutspeanuts fishwheat shellfishsoy
tree nuts (walnuts and pecans
Children will often outgrow their allergy to these food protein
The majority cause
May 21, 2007 smt vi lecture, foodallergy 9
Phatophysiology Allergen in food:
is a protein, glicoprotein or polypeptides Molecular weight > 18 000 Dalton Resistant to heat Resistant to proteolytic enzymes Fish: allergen M, egg: ovomucoid (major), cows
milk:lactoglobulin (BLG), lactalbumin (ALA), bovine serum albumin (BSA), bovine globuline (BGG)
May 21, 2007 smt vi lecture, foodallergy 10
Fish: allergen M egg: ovomucoid (major), cows milk:lactoglobulin (BLG), lactalbumin
(ALA), bovine serum albumin (BSA), bovine globuline (BGG)
Peanut: arachin, conarachin Shrimp: allergen-1, allergen 2 Wheat: albumin, pesudoglobuline, euglobuline
May 21, 2007 smt vi lecture, foodallergy 11
PathogenesisVasoctive amine: histamine,serotonin, protease
lipid mediators: prostaglandin, Leukotriene
allergenTH2 activation by Allergen
IgE class switching in B cell
IgE secreting plasma cell
Binding of IgE to FcέRI on mast cells
Degranulation of mast cell: release mediators
GIT, RT,CV
Cytokine:
Late phase reaction: 2-4 hrs
May 21, 2007 smt vi lecture, foodallergy 12
Predisposing factors associated with Food allergy Genetic : risk of allergy from parent GI immaturity: GI mucosal integrity,
peristaltic , enzymes, acidity, sIgA Allergen exposure : in utero – milk,
breastmilk, norm & tradition in certain area.
Triggering factors are not the cause. Without exposure, triggering factors are not matters. Could be cold, heat, rain, psychological stress, excercise
May 21, 2007 smt vi lecture, foodallergy 13
Clinical manifestation
May 21, 2007 smt vi lecture, foodallergy 14
Clinical manifestation GIT: tingling, itchy mouth, edema
mouth, tongue, palatum, pharyngeal, nausea/vomitting, abdominal cramp, distention, diarrhea, bleeding, protein losing enteropathy
Respiratory tract: Rhinitis, asthma, recurrent chronic cough, difficult breathing
Skin: hives, angioedema, atopic dermatitis
Cardiovascular: drop in blood pressure anaphylaxis shock death
eyes ache,
Food induced anaphylaxis: peanut, sea fish, shrimp, cow’s milk, egg, soy
May 21, 2007 smt vi lecture, foodallergy 15
Symptoms of food allergies
Symptoms typically appear within minutes to two hours after the person has eaten the food to which he or she is allergic.
Individuals with food allergy and asthma appear to be at an increased risk for severe or fatal allergic reactions.
May 21, 2007 smt vi lecture, foodallergy 16
Laboratory investigation Skin test CBC CXR IgE total & Specific
May 21, 2007 smt vi lecture, foodallergy 17
Information obtainable from history Description of symptom & sign Timing from ingestion to onset of symptoms Frequency with which reactions have occurred Time of most recent occurrence Quantity of food required to evoke reaction Associated factors (activity) Medication Reproducibility, esp for subjective symptoms (behaviour,
headache) Potential cross-contact (contamination of other foods, dust
mites)
May 21, 2007 smt vi lecture, foodallergy 18
Diagnosis (Elimination and ) Provocation test
Not done if clinical manifestation is anaphylactic and laryngeal edema
May 21, 2007 smt vi lecture, foodallergy 19
Management Based on symptoms Pharmacotherapy Avoidance
May 21, 2007 smt vi lecture, foodallergy 20
Prognosis Can not be cured Control symptom, reduce intensity Reduce frequency Reduce medication use Reduce absence day Dermatitis reduce after 12 year
May 21, 2007 smt vi lecture, foodallergy 21
•Breast feed at least 4 months (preferably at least 6 months) •Avoid exposure to tobacco smoke and don't smoke during pregnancy •Delay the introduction of solids until age 4-6 months •Introduce new foods one at a time so that allergic reactions can be more readily identified •Introduce rice, vegetables, meat and fruits first •Delay the introduction of egg until at least 12 months •Delay the introduction of nuts and seafood until at least 24 months
Can food allergies be prevented?
May 21, 2007 smt vi lecture, foodallergy 22
There is little or no evidence at this time that severely restricting a mother's diet during pregnancy will prevent food allergy. Indeed, severe restrictions may affect the nutrition of the developing baby.
There is some evidence that certain dietary restrictions during breast feeding may be of some benefit. Any food avoidance should be done with medical or dietetic advice so that maternal nutrition is not compromised.
May 21, 2007 smt vi lecture, foodallergy 23
May 21, 2007 smt vi lecture, foodallergy 24
Case A girl, 5 years old, complaining of red wheal all over the body,
started a day before admission. This is the second episode after the same complaint 4 month ago. Her mother did not notice any possible cause, but, history taking showed that patient is an-egg lover, who has been consumed 4-5 egg everyday since she was 3 years-old. Father has asthma, but mother is generally well. In this case:1. What is the mechanism that underlying the clinical manifestation, if egg
is really a cause of the red wheal?2. Food allergy mediated by immunoglobulin (Ig). Which class of Ig it is ?3. What is the role of loving egg for the development of the disorder?4. What is the importance of parental history?5. Do you have any other question to ask to parents. Name them.6. What test(s) that you plan for the patient?7. What is your suggestion for the management of the case?
May 21, 2007 smt vi lecture, foodallergy 25
Learning task In true food allergy, what mechanism that related
to the clinical manifestation Why food allergy manifests in various organ
systems? What test are needed to support diagnosis of food
allergy? What tests are needed to confirm food allergy ? What are the basic principles of management of
food allergy
top related