Linear porokeratosis presenting as erosions in the newborn period.

The classic appearance of porokeratosis is characterized by a hyperkeratotic annular rim that expands peripherally, leaving an atrophic center. Linear porokeratosis is a variant with collections of such lesions arranged in a linear fashion, usually corresponding to a dermatome or Blaschko's lines. Ulcerations have rarely been reported in patients with porokeratosis. We report an unusual case of linear porokeratosis at birth, with erosions and ulcerations of the face and lower extremity, that eluded diagnosis for nearly a year. Porokeratosis should be considered in the differential diagnosis of erosions in the newborn period.