An Atypical Presentation of Henoch-Schönlein Purpura With Features of Acute Hemorrhagic Edema of Infancy and Koebnerization: A Case Report.

Immunoglobulin A vasculitis, also known as Henoch-Schönlein purpura (HSP), is a type of vasculitis that is most commonly found in children. Palpable purpura is a key feature and is often associated with joint, abdominal, or renal involvement. This case report presents an atypical presentation of HSP in a four-year-old male, characterized by overlapping features of Acute Hemorrhagic Edema of Infancy (AHEI) and Koebnerization (isomorphic response), which complicates the diagnosis. The patient initially presented with redness around his mouth and nose, followed by hematuria and the development of palpable purpura on the lower extremities and buttocks. Vascular swellings were noted on the palms, feet, and face, and cockade purpura appeared on the upper extremities. The patient also exhibited episodic joint pain, genital edema, and Koebnerization on the lower back and buttocks. The diagnosis of this case was challenged by the presence of AHEI-like features and Koebnerization. The patient responded well to treatment with prednisone and colchicine. This atypical case presentation of HSP underscores the clinical overlap between HSP and AHEI, as well as the rare occurrence of Koebnerization in HSP. It emphasizes the importance of recognizing atypical presentations to ensure timely and accurate diagnosis. Further research is required to explore the frequency, pathophysiology, and clinical implications of such cases to enhance diagnostic accuracy and management in pediatric vasculitis.