Which disease is most likely characterized by Koplik spots followed by a maculopapular rash starting behind the ears?

• A. Measles
• B. Rubella
• C. Varicella
• D. Hand-Foot-and-Mouth Disease

Answer: (A)

Koplik spots are tiny bluish-white lesions on the buccal mucosa that appear early in measles and are highly characteristic of this infection. After these spots, the fever and prodromal symptoms (cough, coryza, and conjunctivitis) are followed by a maculopapular rash that typically begins on the face, around the ears and hairline, and then spreads downward to the trunk and limbs. This exact sequence—Koplik spots followed by a facial rash starting behind the ears and moving downward—is the hallmark of measles. Rubella can cause a facial rash but lacks Koplik spots; varicella presents with vesicular lesions in various stages rather than Koplik spots and a predominantly maculopapular eruption; hand-foot-and-mouth disease shows ulcers and vesicles on the hands, feet, and mouth, not Koplik spots.