Concurrent Infections in an Obese Adolescent Female with Chronic Immune Thrombocytopenia

Childhood immune thrombocytopenia (ITP) affects approximately 5 in 100,000 children annually, characterized by autoimmune-mediated platelet destruction and impaired platelet production, resulting in low platelet counts. Approximately 20% of cases progress to a chronic course, defined by persistently low platelet counts (< 10 × 10^9/L) for over 12 months, often necessitating long-term immunosuppressive therapy, which increases susceptibility to infectious complications. We present a case of a 14-year-old obese female with chronic immune thrombocytopenic purpura treated with combined dexamethasone, vincristine, and elthrombopag. She presented with a 7-day history of acute fever and left hip pain, diagnosed with septic arthritis caused by Citrobacter freundii in the left hip, concurrent urinary tract infection due to Escherichia coli, and typhoid fever caused by Salmonella typhi. Surgical drainage of the purulent hip and broad-spectrum intravenous antibiotics for 3 weeks led to significant clinical improvement. Children undergoing long-term immunosuppressive therapy for chronic ITP are at heightened risk of serious concurrent infections, particularly in obese pediatric patients. Obesity’s association with osteoarthritis in weight-bearing joints may further exacerbate infection risks, underscoring the need for additional observational studies to better understand this relationship.