[Acne in the newborn.].

Neonatal acne (NA) is a transitory dermatosis that occurs between the second and fourth weeks of life in 20% of children. This condition is more frequent in males, with a male-female ratio of 4.5:1. Present primary skin lesions are open and closed comedones which can evolve into papules, erythematous pustules and, in rare cases, nodules and cysts. NA topography includes the forehead, cheeks, chin, and eyelids, but occasionally it spreads to the scalp, neck, and trunk. NA occurs due to an elevated production of placental and neonatal androgens (of adrenal origin in both sexes and of testicular origin in males) which cause enlargement of the sebaceous glands and increases the production of sebum. Most cases are mild and transient, but if NA is severe and long-lasting, clinical and paraclinical examination will be necessary to find congenital adrenal hyperplasia or a virilizing tumor of adrenal or gonadal origin. The diagnosis of NA is clinical; its main differential -diagnoses are neonatal cephalic pustulosis, other neonatal vesiculopustular dermatoses, infectious diseases, and acneiform reactions. The resolution of NA is spontaneous. In most cases, the use of a mild dermal cleanser and water will be sufficient. For comedogenic lesions (open and closed comedones), topical retinoids or 20% azelaic acid may be used, as well as some topical antibiotics for inflammatory lesions.