Average age at diagnosis: 15-35 yearsRisk factors: - Nicotine abuse- Familial predisposition: Frameshift mutation in NOD2 gene, HLA-B27 association

Symptoms: - Pain in right lower quadrant, diarrhea, malabsorption, clinical features of abscesses (∼50% of cases) and fistulas (∼30% of cases)- Extraintestinal symptoms are more often (except for PSC): Erythema nodosum, uveitis, sacroiliitis, pyoderma gangrenosum

Pathology:- Skip lesions (discontinuous inflammation)- Hypertrophic lymph nodes- Transmural inflammation→ Noncaseating granulomas with giant cells (Langhans type)→ Infiltrating neutrophilsMacroscopic findings:- Linear ulcers (snail trails)- Other aphthous hemorrhagic mucosa defects (pinpoint lesions)- Cobblestone sign- Fissures, fistulas- Erythema and transmural inflammation

Treatment:- Acute: Corticosteroids- Antidiarrheal agents: Loperamide- 5-Aminosalicylic acid derivatives: Mesalamine, sulfasalazine- Antibiotics: Metronidazole, ciprofloxacin- Immunosuppressants: TNF-α antibodies, azathioprine, methotrexate- Surgical removal