Measles shows up first with a red flat rash, starting on the face and neck. The rash then begins to appear more solid and spreads to the trunk and arms in 2 to 3 days where the spots remain discrete. In contrast, rubella also first appears initially on the face but spreads to the trunk in 1 day. Koplik’s spot, a white spot seen in the mouth, can also be present.
Fitzpatrick’s Color Atlas & Synopsis of Clinical Dermatology
Klaus Wolff, Richard Allen Johnson, Dick Suurmond
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