Which finding is most characteristic of measles on exam in an unimmunized preschooler with fever and morbilliform rash?

Which finding is most characteristic of measles on exam in an unimmunized preschooler with fever and morbilliform rash?

• A. Koplik's spots on buccal mucosa
• B. Rash on palms first
• C. Vesicular rash on trunk
• D. Lacy mucosal lesions

Answer: (A)

Koplik spots are a classic early sign of measles. These tiny bluish-white spots with a red halo appear on the buccal mucosa (inside the cheek, opposite the molars) and are considered pathognomonic for measles. They typically show up 1–2 days before the characteristic morbilliform rash and often help confirm the diagnosis in an unimmunized child who presents with fever and a spreading rash. In contrast, a rash that begins on the palms is not typical for measles, since the measles exanthem starts on the face and then spreads downward. A vesicular rash on the trunk points more toward varicella, and lacy mucosal lesions aren’t characteristic of measles. So the presence of Koplik spots best explains the diagnosis in this scenario.

Koplik spots are a classic early sign of measles. These tiny bluish-white spots with a red halo appear on the buccal mucosa (inside the cheek, opposite the molars) and are considered pathognomonic for measles. They typically show up 1–2 days before the characteristic morbilliform rash and often help confirm the diagnosis in an unimmunized child who presents with fever and a spreading rash. In contrast, a rash that begins on the palms is not typical for measles, since the measles exanthem starts on the face and then spreads downward. A vesicular rash on the trunk points more toward varicella, and lacy mucosal lesions aren’t characteristic of measles. So the presence of Koplik spots best explains the diagnosis in this scenario.