Background: The prevalence of birthmarks and cutaneous skin lesions in newborns vary among sex and race. There are limited reports of birthmarks and cutaneous lesions among Thai neonates.
Objective: To determine the prevalence of birthmarks and cutaneous lesions in Thai newborns and evaluate the association between age, gender, maturity, route of delivery, birth weight and skin lesions.
Material and Method: All of the subjects were healthy newborn infants, who were born between September 2008 to September 2009. They were enrolled and examined for cutaneous lesions by two dermatologists.
Results: 574 neonates were included in this report. The most common pigmentary birthmarks were Mongolian spots (100%), followed by congenital melanocytic nevi (2.4%) and Cafe-au-lait spots (0.3%). The most common vascular birthmarks were salmon patch (16.6%), hemangiomas (0.3%) and vascular malformations (0.3%). Among the cutaneous lesions; the three most common skin lesions were sebaceous gland hyperplasia (78%), Epstein’s pearls (71.3%), and erythema toxicum neonatorum (46.5%).
Conclusion: Mongolian spot was the most frequent birthmark while sebaceous gland hyperplasia was the most frequent cutaneous lesions found among Thai neonates. The prevalence of the cutaneous lesions of newborns differ among countries could possibly be due to race, the age of the infants and the period of observation of the study subjects.

Keywords: Birthmarks, Cutaneous lesions, Vascular birth marks, Neonate