Intestinal permeability in children: variation with age and reliability inthe diagnosis of cow's milk allergy

Objective: To analyse to what extent age may alter intestinal permeability (IP) in children and to assess its reliability according to clinical manife stations in cow's milk allergy (CMA). Design: A routine prospective study w as performed in 200 children (12.5 +/- 23 mo, 0.5-168 mo) presenting with c linical manifestations suggesting CMA. Controls (n = 105) were those with a negative cow's milk challenge, whereas CMA children (n = 95) fulfilled ESP GHAN criteria. Permeability was measured as a percentage of urinary excreti on of lactitol (L, %) and mannitol (M, %) (0.1 g/kg for each, oral absorpti on after a 6h fast, 5h urine collection, analysis by gas chromatography) an d determination of the L/M ratio (L/M, %). Results: In control children, L/ M correlated negatively with age (r -0.33, p = 0.0006), whereas in those wi th CMA no correlation was found. Median L/M was significantly higher in CMA children (n = 95) than in controls (n = 105). 4.35 +/- 7.57% (95% CI 5.30- 8.39%) vs 1.97 +/- 0.87% (95% CI 1.76-2.09%), (p = 0.0001). With a L/M cut- off value defined as mean + 2 SD of controls, in CMA IP exhibited a 68% sen sitivity and a 77% negative predictive value. The highest sensitivity (70%) was seen at ages 6-12 mo and the lowest (58%) at age more than 3 y. An abn ormal IP was seen in 80% of CMA children with digestive manifestations, in 43% with extra-digestive, 68% with mixed and 40% with anaphylactic manifest ations. Conclusion: IP correlates negatively with age in control children and is al tered:lin children with CMA, The test is at its most accurate in the diagno sis of CMA when done at ages 6-12 mo, when there are digestive manifestatio ns.