Patient 1

A 13-day-old term infant was evaluated for bilateral breast enlargement; no tenderness or discharge was evident (figure 1A).

The rest of the physical examination and laboratory were unremarkable. The patient remained well and thriving at regular follow-up; the appearances had completely regressed by 6 weeks.

Patient 2

A term female infant was admitted to hospital at 7 days of life for fever (body temperature 38.2°C) and a swollen right breast with erythematous periareolar skin (figure 1B). The patient was slightly miserable on evaluation; the rest of the physical examination was normal.

Patient 3

A 1-month-old girl was evaluated for a left nipple lesion which had evolved over the previous 2 weeks: the mother described gradual development of sparse similar smaller lesions over the areolar region, which had coalesced (figure 1C). The remaining physical examination was normal and she had a normal newborn examination.

Patient 4

A normal male term newborn was evaluated at 1 month of age for a right nipple lesion with reddish, desquamated areolar and …