This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Infection, Subject name: Medicine
What is the most likely diagnosis for this 19-month-old girl who presented with a 1-week history of an ascending erythematous eruption? 
Select and explain. 
A. Cellulitis, B. Hand, foot, and mouth disease, C. Herpes zoster, D. Lymphadenitis
C: Herpes zoster
Answer: C: Herpes zoster 
Explanation: Answer C. Herpes zosterThe results of a scraping from the base of several vesicles were positive for the varicella-zoster virus. The lesions resolved within 2 weeks of treatment with acyclovir. Herpes zoster is unusual in persons younger than 10 years of age, and when it does occur in this age group, the lesions have a predilection for dermatomes supplied by the cervical and sacral nerves.