HI, thanks for using healthcare magic
Diarrhea is defined as at least 3 bowel movements a day, if it persists for more than 4 weeks then it is called
chronic diarrhea.
Since it has persisted for more than 4 years, it would be best to be seen though a food diary would also be helpful to determine if it is related to specific foods.
Causes of chronic diarrhea include:(1) inflammatory bowel diseases- crohn's disease or ulcerative colitis
(2)infection
(3)high levels of
thyroid hormone
(4)diabetes due to damage to the nerves in the colon
(5)irritable bowel syndrome
(6)side effect of medication
(7)
food intolerance or allergy- as you mentioned, a food diary would determine if this is the case
Blood tests (for infection, thyroid levels and
screening for diabetes) as well as a scope of the intestines may be needed to find the exact cause of your symptoms.
Your GP can refer you to a gastroenterologist who may be able to help you
I hope this helps