What is the differential diagnosis for bright red bleeding per rectum in children?

Differential Diagnosis for Bright Red Bleeding Per Rectum in Children

The differential diagnosis for bright red rectal bleeding in children varies significantly by age, with anal fissures being the most common cause overall, followed by infectious colitis, food protein-induced enterocolitis syndrome (FPIES) in infants, polyps in older children, and inflammatory bowel disease in adolescents. 1, 2, 3

Age-Specific Differential Diagnoses

Infants (0-12 months)

• Anal fissures: Most common benign cause, typically self-limiting 2
• Food protein-induced enterocolitis syndrome (FPIES): Non-IgE-mediated food allergy causing colonic inflammation with rectal bleeding, most commonly triggered by cow's milk or soy 4
  • Colonoscopy shows red, fragile, hemorrhagic mucosa with severe inflammation and increased eosinophils on biopsy 4
  • Can present with chronic symptoms including failure to thrive, or acute symptoms with vomiting and lethargy 4
• Infectious colitis: Bacterial or viral pathogens causing mucosal inflammation 2
• Necrotizing enterocolitis: Life-threatening condition in premature infants 2

Toddlers and School-Age Children (1-12 years)

• Anal fissures: Remain common, associated with constipation 1, 3
• Juvenile polyps: Increasingly common with age, accounting for significant proportion of bleeding 3, 5
  • Critical caveat: 22% of polyps are located proximal to the sigmoid colon and would be missed by sigmoidoscopy alone, making colonoscopy the investigation of choice 5
• Infectious colitis: Including bacterial (Salmonella, Shigella, Campylobacter) and parasitic causes 1, 3
• Meckel's diverticulum: Can present with painless bright red bleeding 3, 6
• Intussusception: Classic "currant jelly" stools, though may present with bright red blood 6

Adolescents (>12 years)

• Inflammatory bowel disease (IBD): Ulcerative colitis and Crohn's disease become more prevalent 5
  • In 72% of pediatric Crohn's disease cases, focal chronically active gastritis is seen on histology, supporting the diagnosis 5
  • Ulcerative colitis presents with diffuse mucosal inflammation and hyperemic, reddish mucosa on colonoscopy 7
• Polyps: Continue to be important differential 3, 5
• Solitary rectal ulcer syndrome: Can present with massive bleeding 8, 3
• Hemorrhoids: More common in adolescents than younger children 8

Critical Diagnostic Approach

Initial Assessment Priorities

• Hemodynamic stability assessment: Approximately 15% of acute presentations can involve hypovolemic shock, requiring aggressive fluid resuscitation 4
• Exclude upper GI source: 10-15% of patients with severe hematochezia have an upper GI bleeding source 9, 8
• Assess for systemic symptoms: Fever, abdominal pain, diarrhea, weight loss, or failure to thrive suggest more serious pathology 4, 1

Endoscopic Evaluation Strategy

• Colonoscopy is the investigation of choice for prolonged rectal bleeding in children, not sigmoidoscopy, due to the 22% miss rate for proximal polyps 5
• When accompanying symptoms exist (abdominal pain, diarrhea, weight loss), perform ileocolonoscopy combined with esophagogastroduodenoscopy to maximize diagnostic yield 5
• Endoscopic evaluation is not routinely required for FPIES diagnosis 4

Common Pitfalls to Avoid

• Never assume hemorrhoids without proper evaluation, as symptoms attributed to hemorrhoids frequently represent other pathology 8
• Do not rely on sigmoidoscopy alone, as this misses more than one-fifth of polyps 5
• Do not use stool tests alone to diagnose FPIES, though they may show eosinophilic debris 4
• Always consider a broad differential, as many infantile gastrointestinal disorders cause overlapping symptoms with chronic FPIES 4

Less Common but Important Causes

• Vascular malformations: Rare but can cause significant bleeding 2, 3
• Very early onset IBD: Rare genetic forms presenting in infancy 2
• Henoch-Schönlein purpura: Vasculitis causing GI bleeding 1, 6
• Hemolytic uremic syndrome: Can present with bloody diarrhea 6