Transient Pigmentary Lines of the Newborn

A 5-week-old African American girl presented for her 2-week well-child visit. She had been born at 35 weeks’ gestation to a mother who was HIV-positive but who took no antiretroviral medications during pregnancy. The infant had been prescribed zidovudine after birth, which was discontinued after 1 month when the girl’s HIV test results were found to be negative. The mother had no concerns, and the newborn was growing and developing appropriately.

Physical examination findings were significant for numerous horizontal hyperpigmented lines crossing the girl’s abdomen. She also had slight stridor on auscultation that worsened with prone positioning. The rest of the physical examination findings were unremarkable. The mother said that her other daughter, now 2 years old, had been born with similar linear hyperpigmentation in the creases of the abdomen, and that they had faded to normal skin before 1 year of life.

Results of the second-stage newborn screening blood test were positive for congenital hypothyroidism; a follow-up test revealed an elevated thyroid-stimulating hormone level with normal levels of free and total thyroxine. On subsequent specialist visits, the girl continued to have stridor and a hoarse cry, along with poor weight gain and widened fontanelles. Levothyroxine was started.

Transient pigmentary lines of the newborn is an exceedingly rare but benign condition that resolves without intervention. Only 8 cases have been reported since 1967. Gibbs first described these lines and postulated that they were the result of in utero irritation of flexed areas.¹ Martín and colleagues reported that they could result from in utero stimulation of melanocyte-stimulating hormone rather than mechanical trauma.²

Of the 8 published cases, 5 were in black children and 2 were in white children; the ethnicity of 1 infant was not identified.³ Additionally, 7 of the 8 cases were in boys; the one girl was white. In all of the cases, the hyperpigmented lines resolved spontaneously within 2 to 8 months.^3,4

References

1. Gibbs RC. Unusual striped hyperpigmentation of the torso: a sequel of abnormalities of epitrichial exfoliation. Arch Dermatol. 1967;95(4):385-386.

2. Martín JM, Jordá E, Alonso V. Transient pigmentary lines of the newborn [letter]. Pediatr Dermatol. 2009;26(6):768.

3. Monteagudo B, León-Muiños E, Suárez-Amor Ó, Labandeira J. Transient pigmentary lines of the newborn [letter]. Actas Dermosifiliogr. 2013;104(6):537-539.

4. Halper S, Rubenstein D, Prose N, Levy ML. Pigmentary lines of the newborn. J Am Acad Dermatol. 1993;28(5 pt 2):893-894.