This is a benign, self-limiting skin rash that occurs in approximately 50% of full term infants (preterm infants are less commonly affected).
The lesions are firm, yellow-white, 1-2mm papules or pustules with a surrounding erythematous flare. They can be sparse or numerous; clustered or widely dispersed. The palms and soles are usually spared.
Reference: Kleigman, R. M., Behrman, R. E., Jenson, H. B., Stanton, B. F. (2007). Nelson Textbook of Pediatrics. 18th Ed. Elsevier/Saunders.