Rationale: Helicobacter pylori infection causes atrophic gastritis in childhood, but atrophic gastritis due to H pylori infection is extremely rare in infancy. The relationship between H pylori infection and chronic diarrhea without protein leakage remains controversial.
Patient concerns: An 8-month-old male infant presented to our hospital with severe watery diarrhea, erythema, and failure to thrive from approximately 1 month after birth. Blood, stool, esophagogastroduodenoscopy, total colonoscopy, and H pylori urease analysis results were positive, thereby suggesting atrophic gastritis.
Diagnoses: Atrophic gastritis and chronic diarrhea due to H pylori infection.
Interventions: We performed H pylori eradication therapy using triple therapy with vonoprazan (6 mg/kg), amoxicillin (300 mg/d), and clarithromycin (120 mg/kg) for 7 days.
Outcomes: From approximately 1 week after the H pylori eradication therapy, the frequency of defecation had decreased, stool shape had improved, and body weight had gradually increased.
Lessons: H pylori infection can cause atrophic gastritis and chronic diarrhea even in infancy. Early eradication therapy for H pylori infection may be useful for prevention of gastric cancer and improvement in growth disorders.