Forschheimer's sign:

Forschheimer spots are a fleeting enanthem seen as small, red spots (petechiae) on the soft palate in 20% of patients with rubella Seen during the prodromal period or on the first day of the rash. They precede or accompany the skin rash of rubella. They are not diagnostic of rubella, as similar spots can be seen in measles and scarlet fever.