Two unusual cases of anhidrosis.

Many disorders produce anhidrosis, including abnormalities of the central or peripheral nervous system. Tumors, infarcts, injuries, or hemorrhages of the brain can be the cause. We describe two patients with anhidrosis due to neurologic causes. One patient had an acquired complete left unilateral anhidrosis without an ipsilateral Horner's syndrome. The other patient showed the second case associated with congenital Horner's syndrome reported in the dermatologic literature. The patient with unilateral anhidrosis had multiple infarcts noted on computed axial tomography and magnetic resonance imaging of his head and spine, which were thought to be the cause of his anhidrosis. Congenital Horner's syndrome is rare, but can be differentiated from other causes of Horner's syndrome by the finding of hypochromia of the affected iris, as in our patient. We present two patients with anhidrosis due to conditions with which the practitioner may not be familiar.