A breastfed baby is jaundiced in the 2nd week of life without fever. What is the likely diagnosis?

Breast milk jaundice is characterized by the development of jaundice in a breastfed infant typically occurring after the first week of life, often peaking between the second and third weeks. This condition arises due to certain substances in breast milk that can inhibit the liver's ability to process bilirubin, leading to elevated bilirubin levels.

In this scenario, given that the infant is jaundiced in the second week of life and is breastfed without other concerning symptoms such as fever or abnormal liver function, breast milk jaundice is the most likely diagnosis. This condition is generally benign and resolves on its own as the infant matures and the liver becomes more efficient in bilirubin metabolism.

Other options like hepatitis would typically present with additional symptoms such as fever or abnormal hepatic function tests, while physiological jaundice usually presents in the first few days after birth. Hemolytic disease can cause jaundice early in life but would likely be accompanied by signs of anemia or other clinical indicators suggesting significant hemolysis. The specific characteristics of the jaundice in this case align closely with breast milk jaundice, making it the most accurate diagnosis.