Congenital miliaria crystallina.

Miliaria crystallina is characterized by intracorneal or subcorneal, 1 to 2 mm, clear, noninflammatory vesicles that typically appear in crops after a severe sunburn or during a febrile illness. They frequently occur in neonates, most likely due to lack of maturation of the sweat duct during the first few days following birth, but are rarely present at delivery. We describe here a patient with extensive miliaria crystallina that was present at birth and review possible theories of the pathogenesis of these lesions.