This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autoimmune Skin Disorders, Subject name: Skin
A 7-year-old boy is brought by parents with abdominal pain, joint aches, and a rash on his legs and feet. He does not have a history of frequent nosebleeds, easy bruising, or other episodes of abnormal bleeding. What is the most likely diagnosis? 
Select and explain. 
A. Acute urticaria, B. DIC, C. Erythema nodosum, D. Henoch-Schonlein purpura
D: Henoch-Schonlein purpura
Answer: D: Henoch-Schonlein purpura 
Explanation: Ans. D. Henoch- Schonlein purpura* Henoch- Schonlein purpura (HSP) is a subtype of acute LCV that is seen more commonly in children and adolescents following an upper respiratory infection.* The majority of lesions are found on the lower extremities and buttocks.* Systemic manifestations include fever, arthralgias (primarily of the knees and ankles), abdominal pain, gastrointestinal bleeding, and nephritis.* Direct immunofluorescence examination shows deposits of IgA within dermal blood vessel walls. Renal disease is of particular concern in adults with HSP.