Atopy Patch Test may help identify and diagnose food allergies in Children

New research found that Atopy Patch Test" (APT) can be a helpful diagnostic tool for identifying the offending food in children with food-induced motility disorders. The trial results were published in the European Journal of Pediatrics. 

Food-induced allergy diseases that are not IgE-mediated gastrointestinal (non-IgE-GI) include a wide range of clinical manifestations. Some of them occurring in the early stages of life present with symptoms like acute abdominal discomfort, persistent crying and unsettled behavior, frequent regurgitation or vomiting, and persistent watery diarrhea, often in combination with poor growth or constipation. These are called the Food Induced Motility Disorders (FPIMD) which improve after dietary elimination of specific food proteins as not all are non-IgE mediated allergies where motility is altered. APT is primarily used for delayed/mixed reactions than IgE-mediated FA. As there is uncertainty in the diagnostic accuracy of APT, researchers conducted a study to evaluate the diagnostic accuracy of the APT compared with the diagnostic gold standard, i.e., the oral food challenge (OFC) in children affected by non-IgE mediated gastrointestinal food allergies, including the evaluation in milk allergic subgroup. 

Food-induced motility disorders (FPIMD) and traditional non-IgE-mediated clinical images were both taken into consideration. Between January 2000 and June 2022, two independent researchers searched Scopus and PubMed to compare the APT diagnostic accuracy to the oral food challenge (OFC). Critical questions were developed using the PICOS (patient, intervention, comparators, outcome, and study design) structure. The QUADAS-2 system evaluated the studies' quality. To determine the pooled sensitivity, specificity, diagnostic odds ratio (DOR), positive likelihood ratio (PLR), and negative likelihood ratio (NLR), as well as their respective 95% confidence intervals (CI), a meta-analysis was conducted. 

Key findings: 

• Out of the 457 citations initially identified via the search (196 on PubMed and 261 on Scopus), 37 advanced to full-text screening, and 16 studies were identified to be included in the systematic review.
• One additional article was also added by searching the reference lists from relevant retrievals.
• Finally, 17 studies were included in the systematic review.
• The analysis showed that APT has a high specificity of 94% (95%CI: 0.88–0.97) in the group of patients affected by FPIMD.
• Data showed a high pooled specificity of 96% and the highest accuracy of APT in patients affected by cow’s milk allergy (AUC = 0.93).

Thus, despite the scarce utilization of the APT test for the diagnosis of FA, the present study concluded that the APT test might be helpful for kids with FPIMD, especially those who have CMA.

Further reading: 

Cuomo, B., Anania, C., D’Auria, E. et al. The role of the atopy patch test in the diagnostic work-up of non-IgE gastrointestinal food allergy in children: a systematic review. Eur J Pediatr (2023). https://doi.org/10.1007/s00431-023-04994-2