Atopy patch test may help early diagnosis of cow-milk allergy in preterm infants. In the retrospective analysis of 5 girls and 9 boys, born at 31 +/- 2 (mean +/- SD) weeks of gestation and presenting digestive symptoms at age 42 +/- 18 days, 10 had a complete recovery following the shift to an exclusive feeding with an amino acid-based formula. Cow-milk-skin prick tests and specific immunoglobulin E were always negative, whereas the atopy patch test was positive in 7 of the 10 infants with complete recovery.