engleski

Atopy patch test in children with cow’s milk protein allergy

Objectives and Study: Atopy patch test (APT) has been increasingly used in children with suspected cow’s milk protein allergy (CMA). We have recently published the results of the test standardization (1). However, diagnostic validity of the test has not been established yet. Aim of the study was to validate the APT by comparing it to the open food challenge test (OFC) in children with clinical symptoms consistent with CMA. Methods: Data on 61 patients (30 girls ; age 3 wks to 4 y, mean age 8.1 mo, median 5 mo) who presented with gastrointestinal (GI) symptoms suggestive of CMA (haematochesia, chronic diarrhea, abdominal colic and vomiting, chronic constipation, poor weight gain) were prospectively collected from January 1st 2008 to December 1st 2009. Beside GI symptoms, 24/61 (39.34%) patients had also symptoms of atopic dermatitis (AD). APTand OFC with cow’s milk based infant formula were performed in all patients. Allergen in the APT was 20 % concentrated milk powder in the petrolatum as a medium. Petrolatum alone was used as a negative control in all patients. The test result was graded as follows: negative (0) - no reaction ; weakly positive (+) - erythema with infiltration ; strongly positive (++) - erythema, infiltration and papules ; and very strongly positive (+++) - erythema, infiltration, papules, vesicles. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for all patients. Results for patients with GI and AD symptoms were compared with patients who presented with GI symptoms alone. Results: APTwas positive in 31/61 patients (50.8%), and 11/ 31 (18.0%) patients had strongly or very strongly positive reaction. From all patients with positive APT, 22/31 had positive OFC. In children with negative APT, OFC has confirmed the diagnosis of CMA in 10/30 (33.33%, false negative). In general, APT yielded sensitivity of 68.75%, specificity 68.97%, PPV 70.97%, and NPV of 66.67%. However, sensitivity for strongly and very strongly reaction was 50%, specificity 95.23%, PPV 90.90%, and NPV was 66.67%. There was no difference in test efficacy in respect to the clinical presentation (P = 0.83, Table 1). Conclusion: In comparison with OFC, only strongly and very strongly positive APT could be used as the diagnostic tool for CMA, irrespective of the clinical presentation.

Atopy patch test; cow’s milk protein allergy

nije evidentirano