More than 50% of babies get this rash around their second or third day of life.

The rash is composed of ½ inch (1.25 cm) to 1 inch (2.5 cm) red blotches with a small white or yellow lump in the center. The number of red blotches can be many and can occur anywhere on the body, except the palms of hands and soles of feet. They can look terrible.

The cause of erythema toxicum is unknown. However, it is harmless the rash goes away by 2 weeks of age.