Differential Diagnosis for 3 Month Old with Dark/Black Colored Stools

• Single Most Likely Diagnosis
  • Melena due to swallowed maternal blood: This is a common cause of black stools in infants, especially if the mother has bleeding gums or is breastfeeding with cracked nipples, leading to the infant swallowing small amounts of blood.
• Other Likely Diagnoses
  • Gastrointestinal bleeding from a milk protein allergy or other allergic reactions: Infants can have allergic reactions to proteins in milk, leading to gastrointestinal symptoms including bleeding.
  • Gastroesophageal reflux disease (GERD) with bleeding: GERD can cause irritation and potentially bleeding in the esophagus or stomach, leading to black stools.
  • Intussusception: Although more commonly associated with abdominal pain and currant jelly stool, intussusception can sometimes present with melena.
• Do Not Miss Diagnoses
  • Volvulus: A condition where a portion of the intestine twists, cutting off blood flow, which can lead to ischemia and potentially life-threatening complications if not promptly treated.
  • Intestinal obstruction: Any condition causing a blockage in the intestines can lead to severe complications, including ischemia and perforation, if not quickly diagnosed and treated.
  • Necrotizing enterocolitis: A serious condition more common in premature infants but can occur in term infants, where portions of the bowel tissue die.
• Rare Diagnoses
  • Hirschsprung’s disease with enterocolitis: A congenital condition affecting the large intestine, leading to severe constipation or intestinal obstruction, and potentially life-threatening enterocolitis.
  • Congenital vascular malformations: Rare conditions where there are abnormalities in the blood vessels that can lead to gastrointestinal bleeding.
  • Ingested substances (e.g., iron supplements, certain medications): Although less common in infants, ingestion of certain substances can cause black stools.