Anhidrotic and achromians lesions in incontinentia pigmenti

Three women subsequently shown to have incontinentia pigmenti (IP) presented with white hairless streaks on the limbs as the predominant cutaneous abnormality. Seven other patients with IP diagnosed in infancy were reviewed to establish the frequency of this sign. It was found in all of them, and in the otherwise unaffected mother of three affected girls. A focal absence of sweating in these lesions is reported here for the first time. There are other similarities with anhidrotic ectodermal dysplasia, suggesting a genetic overlap between these two X-linked conditions.