Differential Diagnosis for a 12-month-old with Bloody Diaper

Single Most Likely Diagnosis

• Anal Fissure: This is a common cause of bloody stools in infants, often resulting from constipation or hard stools that tear the anal lining. The age of the child and the presentation of blood in the diaper make this a likely diagnosis.

Other Likely Diagnoses

• Gastroenteritis: Infections of the gastrointestinal tract can cause bloody stools, especially if the infection is caused by certain bacteria or viruses.
• Food Allergy or Intolerance: Allergies to foods like cow's milk can cause gastrointestinal symptoms, including bloody stools, in infants.
• Intussusception: Although more common in older infants, intussusception (a condition where a part of the intestine slides into an adjacent part) can cause bloody stools and is a significant consideration in infants with abdominal symptoms.

Do Not Miss Diagnoses

• Hirschsprung's Disease: A congenital condition characterized by the absence of nerve cells in parts of the colon, leading to severe constipation and potentially bloody stools. Early diagnosis is crucial for effective management.
• Intestinal Polyp or Other Mass: Though rare, intestinal polyps or other masses can cause bleeding and must be considered to avoid missing a potentially serious condition.
• Infectious Colitis (e.g., Salmonella, Shigella): Certain bacterial infections can cause severe diarrhea and bloody stools, requiring prompt antibiotic treatment.

Rare Diagnoses

• Meckel's Diverticulum: A congenital anomaly of the small intestine that can cause gastrointestinal bleeding due to the presence of ectopic gastric mucosa.
• Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis are rare in infants but can present with bloody stools among other symptoms.
• Vascular Anomalies: Rare conditions affecting the blood vessels of the gastrointestinal tract can cause bleeding.

Each of these diagnoses has a different set of implications for treatment and management, emphasizing the importance of a thorough diagnostic evaluation.