Breastfeeding keratosis: this frictional keratosis of newborns may mimic thrush.

We report the first example, to our knowledge, of a frictional keratosis from exuberant sucking in a breastfeeding infant. A 2-month-old girl was referred for evaluation of a well-demarcated, nonsloughing white keratotic plaque of the lower lip mucosa, just inside the vermilion border. The plaque had a slightly irregular surface, had no surrounding erythema, and was the only such plaque in the mouth. It had been present for at least 3 weeks and had been unsuccessfully treated by her pediatrician via oral Mycostatin (nystatin). Her parents sought a second opinion when the infant was prescribed a full course of oral Diflucan (fluconazole). A cytopathology smear (Papanicolaou test) revealed abundant mature keratinocytes with no evidence of Candida. The mother admitted that the infant "worked hard" at sucking during breastfeeding and continued sucking long after feeding. The parents were unaware of any other habit or potential irritation of the lips. After 3 months of age the infant's sucking pattern became more "normal" and the keratosis disappeared; it did not recur during 3 years of follow-up. We propose the term "breastfeeding keratosis" for this entity.