Causes of linear or curvilinear hyperpigmentation in childhood include linear and whorled hypomelanosis, epidermal nevus, postinflammatory hyperpigmentation, and incontinentia pigmenti. Zhu et al1 described 2 infants with palpable, bilateral, curvilinear hyperpigmentation of the calves that did not follow Blaschko lines, appeared shortly after birth, and histologically demonstrated lentiginous melanocytic hyperplasia and basal layer hyperpigmentation. They called this disorder congenital curvilinear palpable hyperpigmentation. We report 5 similar cases and expand the spectrum of findings. We suggest that this hyperpigmentation results from postinflammatory changes from elastic bands of socks rather than a congenital disorder.
Berk DR, Tapia B, Lind A, Bayliss SJ. Sock-Line Hyperpigmentation: Case Series and Literature Review. Arch Dermatol. 2007;143(3):423-431. doi:10.1001/archderm.143.3.428