Lactose intolerance

From IKE

Lactose intolerance is intolerance to lactose. Primary intolerance is extremely uncommon at birth, though it is very common in non-white populations beginning after age 5. Secondary lactose intolerance is very common, and may last up to three months after acute infection. They may be due to other malabsorptive disease. Both lactose intolerance types may be diagnosed by typical history, and response to lactose-free diet.