What are the signs and symptoms of a Crohn's (Crohn's disease) flare?

Signs and Symptoms of a Crohn's Disease Flare

During a Crohn's disease flare, patients experience diarrhea (at least 10 loose stools daily in severe cases), daily colicky abdominal pain, weight loss, and fever—with the critical distinction that inflammation often persists without symptoms, making objective assessment essential. 1

Core Gastrointestinal Manifestations

• Diarrhea is the hallmark symptom, with severe flares producing at least 10 loose stools per day, though milder exacerbations may present with fewer bowel movements 1, 2
• Abdominal pain occurs daily during moderate to severe flares, typically colicky in nature and reflecting active intestinal inflammation 1, 3
• Weight loss develops from both malabsorption and reduced oral intake, serving as a key indicator of disease severity 1, 4
• Rectal bleeding may occur, though it is less prominent than in ulcerative colitis 2, 5

Perianal and Anorectal Symptoms

• Perianal manifestations include anorectal pain, bowel urgency, fecal incontinence, perianal discharge, and tenesmus 1
• Perianal disease (fistulas, abscesses) affects up to one-third of patients and may be the presenting feature of a flare 3

Systemic Symptoms

• Fever is more common in Crohn's flares than ulcerative colitis and helps distinguish between the two conditions 1, 3
• Malaise and anorexia are systemic features that differentiate Crohn's exacerbations from other inflammatory bowel conditions 1, 3
• Fatigue is a debilitating symptom that accompanies active disease 6, 7

Laboratory Abnormalities

• Elevated C-reactive protein (CRP) reflects the inflammatory burden during active disease 8, 1, 2
• Low serum albumin indicates both inflammation and poor nutritional status 8, 1
• Anemia commonly develops from chronic inflammation, blood loss, or nutritional deficiencies 1, 2
• Elevated fecal calprotectin serves as a noninvasive marker of intestinal inflammation 8, 4

Disease Severity Classification

The Crohn's Disease Activity Index (CDAI) provides objective severity assessment: 8

• Moderate disease: CDAI 220-450
• Severe disease: CDAI >450
• The index incorporates stool frequency, abdominal pain severity, general well-being, extraintestinal manifestations, antidiarrheal medication use, abdominal mass presence, hematocrit, and weight deviation 8

The Harvey-Bradshaw Index (HBI) offers a simpler clinical assessment using general well-being, abdominal pain, liquid stool frequency, abdominal mass, and extraintestinal manifestations 8

Extraintestinal Manifestations

• Musculoskeletal: Inflammatory arthropathies and arthralgia occur frequently 8, 2
• Dermatologic: Erythema nodosum and pyoderma gangrenosum may develop 8, 2
• Ocular: Scleritis and uveitis can accompany disease flares 2, 5
• Hepatobiliary: Primary sclerosing cholangitis and cholelithiasis are associated complications 8, 2
• Renal: Nephrolithiasis develops in some patients 8, 2

Critical Pitfalls to Avoid

Symptom-inflammation discordance: Inflammation frequently persists without gastrointestinal symptoms, potentially causing progressive bowel damage even when patients report feeling well—objective measures (endoscopy, imaging, or biomarkers like CRP/fecal calprotectin) are essential when making treatment decisions 8, 1

Intestinal obstruction from strictures may mimic a flare with pain and altered bowel habits but requires different management (potential surgery rather than immunosuppression escalation) 1, 3

Abscess formation presents with fever and abdominal pain but needs drainage rather than immunosuppression alone—imaging is critical to exclude this complication before escalating immunosuppressive therapy 1

Alternative symptom causes must be considered, including bile acid diarrhea, small intestinal bacterial overgrowth, superimposed irritable bowel syndrome, or fibrotic strictures—these require different treatment strategies than active inflammation 8

Monitoring Strategy

When assessing for a flare, objective measures of inflammation should be obtained rather than relying solely on symptoms: 8

• Endoscopic assessment (colonoscopy with ileoscopy) to visualize ulcerations
• Cross-sectional imaging (MR enterography or CT enterography) to assess small bowel involvement and complications
• Biomarkers (CRP, fecal calprotectin) as surrogate markers when endoscopy/imaging cannot be performed immediately

The absence of ulcerations on endoscopy defines endoscopic remission, which predicts better long-term outcomes than symptomatic improvement alone 8