*Diagnostic Tools of Food AllergySumadionoPediatric Department Fac. of Medicine Gadjah Mada University Yogyakarta

Food Allergy Diagnosis StepsAllergy HistoryClinical Signs and SymptomsSkin Test (skin prick test, atopy patch test)Specific IgE test (RAST)Elimination & Provocation test

*

Unproven methods: Procedures used in diagnosis and treatment that lack scientific credibility.

Have not been shown to have clinical efficacy

Commercial interests

Invalid tests

Cytotoxic testingplacing a drop of the persons blood onto a glass microscope slide which has a spesific dried food already attached to the glass.

Provocation-Neutralizationinjecting a various chemicals, pollens, food, hormone or toxins into the skin of person results any symptom = provocation dose.Smaller doses and concentrations of that same substances are injected until no symptoms occur = neutralization dose.

More D,MD. Controversial and Unproven Tests in the Diagnosis of Allergies. 2011

Invalid tests Electrodermal Diagnosis

Diagnose food or other allergies through changes in skin resistance by measuring an electric current. The person will hold a glass vial containing the food in question in one hand, and source of electrical current in the other hand.

More D,MD. Controversial and Unproven Tests in the Diagnosis of Allergies. 2011

Invalid tests Electrodermal Skin Test VEGA test - Bioresonance

Invalid tests Applied Kinesiology detection a change in a persons muscle strenght

Reaginic Pulsemeasures a persons pulse after eating a particular food.

Body Chemical Analysistrace amount of chemicals measured in body fluids, hair and tissue that can leads to allergy symptoms and disease.More D,MD. Controversial and Unproven Tests in the Diagnosis of Allergies. 2011

*

Food Allergy Diagnosis StepsAllergy HistoryClinical Signs and SymptomsSkin Test (skin prick test, atopy patch test)Specific IgE test (RAST)Elimination & Provocation test

*

Food allergy: clinical manifestations IgE IgE/Non-IgE Non-IgEUrticaria/angioedemaRhinitis /AsthmaAnaphylaxis

Oral allergic syndromeGastrointestinal symptoms

Atopic dermatitis

Eosinophilic gastro-intestinaldisordersProtein-induced proctocolitis/enterocolitis

Celiac diseaseContact dermatitisHerpetiform dermatitis

Adapted from J Allergy Clin Immunol. 1999;103:717-728

Generally begins in early infancy Characterized by typical distribution, extreme pruritus, and chronically relapsing courseCutaneous food hypersensitivities:atopic eczema

Acute Urticaria and Angioedema:The most common symptoms of food allergic reactions

Chronic Urticaria:Food allergy is an infrequent cause of chronic urticaria and angioedemaCutaneous food hypersensitivities

IgE mediated: respiratory manifestations

AsthmaAn uncommon manifestation of food allergyUsually seen with other food-induced symptoms

RhinoconjunctivitisUsually seen during positive controlled challenge tests, but occasionally reported by patients

IgE Mediated: systemic reactionanaphylaxis/anaphylaxis syndrome Food-induced anaphylaxis - Rapid-onset - Multi-organ system involvement - Potentially fatal - Any food, highest risk: peanut, nut, seafood, milk, egg

Food-dependent - exercise-induced - Associated with a particular food - Associated with eating any food

An immediate reaction (1- 2 hours) is suggestive of an IgE mediated reaction to foods Diagnosing IgE-mediated food hypersensitivity disordersMedical history: Timing of reactionAdapted from Adverse Reactions to Foods Committee, Spanish Society of Allergy and Clinical Immunology Alergol Inmunol Clin 1999; 14: 50-62.

Allergens eliciting a wheal of at least 3 mm greater than the negative control

Overall positive predictive accuracy is 50 %Negative predictive accuracy > 95 %Diagnosing IgE-mediated food hypersensitivity disorders+Diameter 3 mm

Skin Prick Test

Prick: Reproducible, sensitive, not irritantPrick-prick: Use raw or cooked food. Highly recommended for fruits and vegetables (commercially prepared extracts are generally inadequate because of the lability of the allergens, so the fresh food must be used for skin testing)Diagnosing IgE-mediated food hypersensitivity disorders Skin tests

Impracticality of skin testingSkin disorder, drug inhibition, uncooperatvie patients

Prevention of systemic reactionsPrior history of anaphylactic reaction, severe asthma,

Convenience

DisadvantagesCost, Results delayed

IgE SpecificRadioimmunosorbant Assay (RAST)

Diagnosis: elimination diets and food challengesElimination diets (1 - 6 weeks): - Eliminate suspected food/s, or - Prescribe limited eat only diet, or - Elemental diet

Oral challenge testing: - Physician supervised - Emergency room medications must be available

*

Oral Challenge TestChallengeRecord baseline symptomsEat and average portion of the pure food within 5 minutesRecord symptoms over the 1st hourMay repeat a feeding in no symptoms in the 1st hourObserve patient a minimum of 2 hours

*Atopy Patch Test (APT)Vivo

*

*

- Elimination & Provocation TestSpecific IgEElimination & Provocation Test - Atopy Patch Test

- Endoscopy, Biopsy of Gut, Skin

THANK YOU

**********