Diagnostic accuracy of the atopy patch test in children with food allergy-related gastrointestinal symptoms.
BACKGROUND
Little is known about the diagnostic accuracy of atopy patch tests (APT) in the clinical practice of pediatric gastroenterology. Moreover, APTs containing purified food extracts have recently become available, but their diagnostic accuracy is largely undefined.


METHODS
We evaluated the diagnostic accuracy of food challenge, skin prick test (SPT), serum specific IgE determination, and APT using fresh food and commercial food extracts in parallel in children referred for suspected food allergy-related gastrointestinal symptoms.


RESULTS
Eighty-nine food challenges were performed in 60 patients (38 boys, median age 23 months, range 3-48 months): 31 tested positive for cow's milk (CM), 19 for hen's egg (HE), and two for wheat. Specific immunoglobulin E (IgE) determination, and SPT, respectively, were positive in 7/31 and 14/31 of patients with cow's milk allergy (CMA), and in 7/19 and 7/19 with HE allergy. The results of APT with fresh food vs a commercial assay were (1) CM: sensitivity: 64.5%vs 6.4%, specificity 95.8%vs 95.6%, positive predictive value (PPV) 95.2%vs 66.6% and negative predictive value (NPV) 67.6%vs 43.1%; (2) HE: sensitivity 84.2%vs 5.2%, specificity 100%vs 100%, PPV 100%vs 100% and NPV 75.0%vs 33.3%.


CONCLUSIONS
Atopy patch test is a useful tool in the diagnostic work up of children with food-allergy-related gastrointestinal symptoms. The diagnostic accuracy of ATP was higher with fresh food than with commercial food extracts.
Canani
R Berni
RB
Department of Pediatrics and European Laboratory for the Investigation of Food Induced Diseases, University of Naples Federico II, Naples, Italy.
Ruotolo
S
S
Auricchio
L
L
Caldore
M
M
Porcaro
F
F
Manguso
F
F
Terrin
G
G
Troncone
R
R
D000818:Animals; D002648:Child; D002675:Child, Preschool; D021181:Egg Hypersensitivity / Q000175:diagnosis; D005260:Female; D005512:Food Hypersensitivity / Q000150:complications*; D005519:Food Preservation; D005767:Gastrointestinal Diseases / Q000209:etiology*; D006801:Humans; D007073:Immunoglobulin E / Q000276:immunology; D007223:Infant; D008297:Male; D016269:Milk Hypersensitivity / Q000175:diagnosis; D010328:Patch Tests / Q000592:standards*; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021182:Wheat Hypersensitivity / Q000175:diagnosis
D007073:Immunoglobulin E