This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Vasculitis, Subject name: Medicine
A 9 year old boy presented to the casualty with high fever, pruritic erythematous rash, joint pain and lymph node enlargement. There is a history of upper respiratory tract infection for which he was on cefaclor - 7 days completed of a 10 day course. The most likely diagnosis is? 
Select and explain. 
A. Serum sickness like illness, B. Hemolytic-uremic syndrome, C. Kawasaki disease, D. Type III hypersensitivity
A: Serum sickness like illness
Answer: A: Serum sickness like illness 
Explanation: Serum sickness like reaction can occur following the use of ceain drugs, especially cefaclor in children. It presents with an uicarial / purpuric rash, ahritis, lymphadenopathy and fever. But unlike true serum sickness (type III hypersensitivity response), it is not caused by circulating immune complexes.