What should you know about galactosemia and lactose intolerance?

Galactosemia is an inherited metabolic disorder in which the body cannot process galactose normally. It can become serious early in life, particularly after milk feeds, and is usually identified through newborn screening or urgent assessment of an unwell infant.

Lactose intolerance happens when the small intestine makes too little lactase, the enzyme that breaks lactose into absorbable sugars. Undigested lactose can draw water into the bowel and be fermented by gut bacteria, causing bloating, abdominal pain and diarrhoea. It is not the same as a milk allergy.

Do not diagnose either condition from symptoms alone. For a baby with poor feeding, vomiting, jaundice, unusual sleepiness or poor growth after milk feeds, seek urgent medical assessment and do not make formula changes without specialist guidance.

For suspected lactose intolerance, record foods, timing and symptoms, then discuss testing or a supervised dietary trial. A dietitian can help preserve calcium, protein and other nutrients when dairy is reduced. Lactose-free products may help some people, while others tolerate small portions with meals.

Get urgent care for an infant who is repeatedly vomiting, very sleepy, dehydrated, jaundiced or not feeding. These symptoms can have causes that require prompt treatment.

Arrange routine review for ongoing diarrhoea, weight loss, persistent pain, blood in stool or symptoms that continue despite dietary changes. A clinician can check for coeliac disease, infection or another bowel problem.

Could this be lactose intolerance, galactosemia, milk allergy or another condition? Which test is suitable? If dairy is reduced, how will calcium and vitamin needs be met? Is a dietitian referral appropriate?