The severity of Crohn's disease can be assessed based on clinical manifestations. No systemic symptoms, abdominal tenderness, masses, and obstruction indicate mild severity; significant abdominal pain, diarrhea, systemic symptoms, and complications indicate severe severity; those in between are considered moderate.

Clinically, the Harvey-Bradshaw index (simplified CDAI) is more convenient and practical. A score of ≤4 indicates remission; 5-8 indicates moderate activity; and ≥9 indicates severe activity.

Complications of Crohn's disease include:

A. Joint Pain/Arthritis

B. Iritis/Uveitis

C. Erythema Nodosum/Pyoderma Gangrenosum/Oral Ulcers

D. Anal Fissures/Fistulas/Abscesses

E. Other Fistulas

F. Fever >38℃ in the past week