Medical history

Asking questions about your medical history is an important part of diagnosing lactose intolerance. Your doctor may ask you about:

• Your symptoms and when they occur. To help make a diagnosis, your doctor may ask you to keep track of what and when you eat and the type of symptoms you have.
• Recent illnesses, long-term diseases, or surgeries involving your stomach or intestines.
• Your family history of lactose intolerance.
• Your ethnic background. Most people in the world become somewhat lactose-intolerant as adults. People with a northern European heritage usually are the exception.

If your baby may have lactose intolerance, you may be asked if he or she:

• Has diarrhea often.
• Seems hungry all the time.
• Has gained little or no weight.
• Seems irritable.

Physical exam

The physical exam for lactose intolerance includes examining your belly. You may also be asked to bring in a sample of your stool. The stool of a person with lactose intolerance is usually loose or watery. It also can be foamy.