Primary lactase deficiency is caused by a genetic mutation that reduces the activity of the lactase enzyme, which is responsible for breaking down lactose, a sugar found in dairy products.
Primary lactase deficiency is diagnosed by a simple breath test that measures the amount of hydrogen present in the breath when a patient consumes lactose.
Differential diagnoses for primary lactase deficiency include secondary lactase deficiency, which can be caused by a variety of conditions such as celiac disease, Crohn’s disease, and small intestinal bacterial overgrowth; and congenital lactase deficiency, which is a rare inherited disorder.
Treatment for primary lactase deficiency involves eliminating or reducing lactose in the diet and taking over-the-counter lactase supplements.
The prognosis for primary lactase deficiency is generally good, as long as patients follow their doctor’s recommendations for dietary changes and lactase supplementation.