What are the symptoms?

Symptoms occur at different times in different people. Sometimes they appear in childhood, but for other people, the symptoms appear when they are adults. Symptoms aren't always in the digestive system, the NIDDK says. Although chronic diarrhea and recurrent abdominal pain are symptoms, irritability and depression also can be symptoms.

Other symptoms, from the NIDDK:

  • Recurring abdominal bloating
  • Weight loss
  • Pale, foul-smelling stool
  • Unexplained anemia
  • Gas
  • Bone pain
  • Behavior changes
  • Muscle cramps
  • Fatigue
  • Delayed growth
  • Failure to thrive (infants)
  • Pain in joints
  • Seizures
  • Tingling numbness in legs
  • Pale sores inside the mouth
  • Painful skin rash
  • Tooth discoloration
  • Missed menstrual periods