Skin colonization by Malassezia species in neonates: a prospective study and relationship with neonatal cephalic pustulosis.

Objectives: To assess skin colonization by Malassezia species in full-term healthy newborns, to investigate factors associated with colonization, and to look at acnelike cephalic pustulosis associated with this carriage.

Design: Samples were obtained from neonates and their mothers 0 to 5 days after birth and again 3 weeks later. Clinical patterns of common acnelike pustulosis were reported as mild (<10 papulopustules), moderate (> or =10 papulopustules), or absent. Direct examination and culture of sample. Identification of yeasts was based on microscopic and physiologic criteria.

Setting: A maternity hospital and the pediatric dermatology unit of a university hospital.

Participants: Consecutive series of 102 neonates and their mothers.

Main Outcome Measures: Incidence of skin colonization and type of Malassezia species found in neonates and correlation with neonatal cephalic pustulosis (neonatal acne).

Results: At the first visit, 11 neonates and 36 mothers had cultures positive for Malassezia. Malassezia sympodialis and Malassezia globosa were preferentially cultured. At 3 weeks, 29 (52%) of 56 neonates and 18 (32%) of 56 mothers had cultures positive for only M sympodialis and M globosa. Breastfeeding was not associated with a higher prevalence of Malassezia carriage in neonates. Malassezia colonization was higher when pustulosis was more severe and M sympodialis was found in pustules.

Conclusions: Malassezia colonization begins at birth and increases in the first weeks of life. A high prevalence of M sympodialis in neonates is noted from birth. Its association with neonatal acne is confirmed. Further investigation is needed to study the role of sebum secretion rate and quality in the neonatal period.