Group A β-hemolytic Streptococcus causes strep throat.  Certain strains of Streptococcus produce a toxin that causes scarlet fever - paleness around the mouth, a bright red tongue, and a fine, red, bumpy rash (that feels like sandpaper).  Scarlet fever occurs around the same time as the sore throat symptoms and lasts for a few days.

Photo - This patient revealed a scarlet fever rash on the volar surface of the forearm due to group A Streptococcus bacteria. The scarlet fever rash first appears as tiny red bumps on the chest and abdomen that may spread all over the body. Looking like a sunburn, it feels like a rough piece of sandpaper, and lasts about 2-5 days. CDC. 1975. Used with permission.