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Updated September 03, 2013.

This is another example of Koplik spots inside the mouth of someone who is suffering from measles. The spots are the 1 to 2mm blue-white lesions across from the molars.

Koplik spots only occur in measles, and they help doctors tell the difference between the start of a measles infection or the start of an influenza infection. People with influenza don't get Koplik spots.