Rapidly Progressive Cytophagic Histiocytic Panniculitis in a Child Triggered by Trauma and Scrub Typhus: A Dramatic Response to Cyclosporine.

Cytophagic histiocytic panniculitis (CHP) is a rare and potentially life-threatening inflammatory panniculitis characterized by lobular lymphohistiocytic infiltration and cytophagic "bean-bag" histiocytes. Because its early features overlap with infectious panniculitis and hemophagocytic lymphohistiocytosis (HLH), diagnosis is often delayed, contributing to significant morbidity. We describe a rapidly progressive pediatric case of CHP triggered by antecedent trauma and scrub typhus infection. A 10-year-old girl presented with seven days of high-grade fever and painful erythematous nodules over the extremities and trunk. Ten days prior, she had sustained a rope-induced traumatic ulcer on her leg, followed by persistent fever and progressive nodular lesions. Clinical examination revealed pallor, tachycardia, hepatosplenomegaly, and multiple tender subcutaneous nodules. Laboratory evaluation demonstrated severe anemia, thrombocytopenia, leukopenia, elevated liver enzymes, markedly raised inflammatory markers, and hyperferritinemia, with positive scrub typhus immunoglobulin M (IgM) serology and otherwise negative infectious and autoimmune workup. Despite treatment with doxycycline, broad-spectrum antibiotics, and supportive care, the patient's condition worsened. Skin biopsy revealed dense lobular panniculitis with numerous cytophagic histiocytes containing erythrocytes and nuclear debris, confirming the diagnosis of CHP. High-dose intravenous methylprednisolone was initiated, resulting in only partial clinical improvement. The subsequent addition of cyclosporine at a dose of 5 mg/kg/day led to rapid defervescence within 48 hours, the regression of nodules, and the normalization of hematological parameters. This dramatic response highlights the therapeutic value of cyclosporine in severe or steroid-refractory CHP. This case underscores the importance of considering CHP in children presenting with febrile panniculitic nodules unresponsive to antimicrobial therapy, particularly when associated with cytopenias and systemic inflammation. Early dermatologic evaluation, timely biopsy confirmation, and the prompt initiation of immunosuppressive therapy are essential to prevent progression to HLH and ensure favorable outcomes. Our report adds to the limited pediatric literature on CHP and emphasizes the need for heightened clinical awareness and cyclosporine-based immunomodulation in rapidly progressive disease.