Whipple disease: A form of inability to absorb nutrients from the intestine. It can affect any part of the body, leading to arthritis and then weight loss, cough, fever, diarrhea, hypotension (low blood pressure), abdominal swelling, increased skin pigmentation, and severe anemia. Whipple disease has been discovered to be due to a type of bacteria named Tropheryma whippelii. Whipple disease is treated with antibiotics. Some patients relapse and need long-term, even life-long, treatment.