Lactose Intolerance Clinical Presentation

Updated: Dec 04, 2019
  • Author: Praveen K Roy, MD, MSc; Chief Editor: Burt Cagir, MD, FACS  more...
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History and Physical Examination


Patients with lactose intolerance may include history of abdominal fullness/bloating, nausea, abdominal pain, diarrhea, and flatulence. [18, 19] Symptomatic variability is dependent on the amount of ingested lactose, the residual lactose activity, and the small bowel transit time. [11] It appears that 12 g of lactose in one intake, with about 18 g of lactose over the course of a day, is tolerable for most lactose-intolerant individuals. [11]

The symptoms of irritable bowel syndrome (IBS) resemble those of lactose intolerance and can easily be confused. Some patients with IBS can also have lactose intolerance. Restriction of milk products in these patients may relieve the symptoms of IBS. [20, 21]

Physical examination

Physical examination findings very often are normal. Borborygmi may be present.