Signs and Symptoms of Crohn's Disease
Crohn's disease typically presents with chronic abdominal pain, diarrhea, and weight loss, most commonly affecting the terminal ileum and colon, though any part of the gastrointestinal tract from mouth to anus can be involved. 1
Primary Gastrointestinal Symptoms
The cardinal symptoms that should prompt consideration of Crohn's disease include:
- Chronic diarrhea (with or without blood), which may be accompanied by urgency and is particularly significant when occurring nocturnally 1, 2
- Abdominal pain, often colicky in nature and frequently localized to the right lower quadrant when the terminal ileum is involved 3, 4
- Weight loss, which correlates with more severe disease activity and is a key distinguishing feature from functional bowel disorders 1, 2
- Rectal bleeding, though less prominent than in ulcerative colitis 4
Constitutional and Systemic Symptoms
Beyond the gastrointestinal tract, patients commonly experience:
- Fever, indicating severe inflammatory activity and potential complications 2, 3
- Fatigue, which significantly impacts quality of life 4
- Growth failure and delayed puberty in pediatric patients, sometimes presenting before obvious gastrointestinal symptoms 3
Extraintestinal Manifestations
Nearly half of patients develop manifestations outside the bowel 3:
- Arthritis or arthralgia affecting peripheral or axial joints 5, 3
- Dermatologic findings including erythema nodosum and pyoderma gangrenosum 5, 3
- Ocular involvement such as uveitis 3
- Perianal disease including fistulas, abscesses, and skin tags, which is a particularly important predictor of aggressive disease 5, 1, 6
Disease Complications and Patterns
The transmural nature of inflammation leads to characteristic complications:
- Stricturing disease causing obstructive symptoms, developing in up to 50% of patients over time 3
- Penetrating complications including fistulas (most commonly perianal), abscesses, and sinus tracts 5, 6
- Inflammatory masses detectable on physical examination or imaging 5
The disease follows a relapsing-remitting course, with approximately 50% of patients experiencing a flare in any given year 1. Symptoms may vary based on disease location—upper gastrointestinal involvement (occurring in 0.5-13% with concurrent ileocolonic disease) presents more frequently with nausea, anorexia, and colic-like pain 7.
Key Clinical Predictors
Certain features at presentation predict more aggressive disease requiring earlier biologic therapy 8:
- Young age at diagnosis (particularly adolescence or early adulthood) 3
- Extensive disease involvement at presentation 8
- Deep ulcerations on endoscopy 8
- Perianal involvement 8
Important Diagnostic Caveats
Symptoms alone cannot distinguish Crohn's disease from functional disorders or other inflammatory conditions. 2 The Crohn's Disease Activity Index, while used in clinical trials, correlates poorly with objective inflammation and can be elevated in patients with irritable bowel syndrome-like symptoms without active disease 5, 2. Therefore, objective confirmation with elevated inflammatory markers (C-reactive protein, fecal calprotectin >250 μg/g) and endoscopic or imaging findings is essential 5, 2.
Functional gastrointestinal symptoms frequently coexist with Crohn's disease and may persist even after mucosal healing, confounding assessment 2. In endemic areas, intestinal tuberculosis can mimic Crohn's disease; features suggesting tuberculosis include night sweats, concomitant pulmonary involvement, and prominent abdominal lymphadenopathy 1.