Background and Aims: Henoch-Sch?nlein purpura (HSP) is a multi-system inflammatory disease of the small blood vessels, involving skin, joints, gastrointestinal tract, kidneys and other areas. The clinical manifestations of HSP are nonspecific, and the diagnosis is more difficult for those with gastrointestinal symptoms preceding the onset of purpura rash. This study was conducted to summarize and analyze the clinical characteristics and treatment experience of abdominal HSP for improving the early recognition of this condition. 
Methods: The clinical data of 45 HSP patients with abdominal pain as the predominant symptom admitted to Xiangya Hospital, Central South University from January 2012 to January 2018 were retrospectively analyzed. 
Results: Among the 45 patients with abdominal HSP, 34 cases were males and 11 cases were females, with a male to female ratio of 3.1:1; the average age of onset was (31.1±18.6) years, and the majority of them were adolescents under 18 years old; autumn and winter were the most common seasons of onset. Twenty-four patients (53.3%) had the abdominal pain as the first symptom, which was most frequently occurred in the middle and upper abdominal regions, and mainly presented as intermittent colicky pain, 14 patients (31.1%) had a purpura rash as the first manifestation, and 5 patients (11.1%) had a concomitant abdominal pain and rash, and the other associated symptoms included nausea, vomiting, hematochezia, abdominal distention, and pain in both knees. In the laboratory examination, 32 patients (71.1%) had an elevated white blood cell count comprised mainly of neutrophils, 13 patients (28.9%) had a positive urinary protein test, 13 patients (28.9%) had red blood cells in the urine, 35 patients (77.8%) showed decreased albumin level, 27 patients (60.0%) showed increased C-reactive protein (CRP) level, 33 patients (73.3%) were positive for fecal occult blood test, and 4 patients (16.0%) had an increased immunoglobulin A (IgA) level. Thirty-two patients underwent food intolerance tests, 19 cases (59.4%) sensitized to food allergens, which mainly were heterologous proteins. Thirty-three patients (73.3%) underwent gastroscopic examination, and the lesions mainly involved the duodenal bulb and descending duodenum; 
26 cases had a colonoscopic examination, and the lesions mainly involved the terminal ileum; 3 cases were subjected to enteroscopic examination, and the lesions mainly involved the middle and lower ileum. Endoscopic findings were mainly congestion and edema of the gastrointestinal mucosa and lamellar erosion, and some lesions were accompanied by ulcerations. Seven patients (15.6%) underwent abdominal CT examination, all which showed intestinal wall thickening, and some were accompanied by retroperitoneal and mesenteric lymph node enlargement. Twelve cases (26.7%) underwent biopsy, and the results suggested nonspecific inflammation of the mucosa, with infiltration of eosinophils and plasma cells in some cases. All patients received comprehensive treatment after diagnosis, and the gastrointestinal symptoms and rash were significantly relieved 40 cases (88.9%) after glucocorticoid treatment. Recurrence occurred in 6 cases (13.3%), with a time to recurrence ranged from 1 month to 24 months. 
Conclusion: In abdominal HSP, the purpura rash usually appears later than gastrointestinal symptoms, which lacks specific symptoms and signs, and is likely misdiagnosed. Early gastrointestinal endoscopic examination should be performed in clinical practice, so as to improve the diagnosis and understanding of this condition.