A child with a history of fever and a vesicular rash is most likely suffering from which condition?

A child with a history of fever and a vesicular rash is most likely suffering from hand, foot, and mouth disease. This condition, commonly caused by coxsackievirus, is characterized by the presence of vesicular lesions on the hands, feet, and inside the mouth, often accompanied by fever. The rash typically appears after the onset of fever and can be itchy or painful.

In this scenario, the combination of fever and a vesicular rash strongly aligns with hand, foot, and mouth disease due to its distinctive presentation. Other conditions like chickenpox, measles, and scarlet fever generally present with different characteristics. For example, chickenpox also features a vesicular rash but may have more systemic manifestations and a different distribution pattern, as it typically starts on the trunk and face. Measles usually presents with a characteristic rash that appears after a prodromal phase with cough, conjunctivitis, and Koray spots. Scarlet fever is primarily indicated by a sandpaper-like rash and is closely associated with a streptococcal throat infection, not primarily with vesicular lesions.

Thus, the clinical presentation of fever followed by a vesicular rash suggests hand, foot, and mouth disease as the most likely diagnosis.