Amyotrophic lateral sclerosis: histologic, histochemical, and ultrastructural abnormalities of skin.

We studied the reticular dermis in patients with amyotrophic lateral sclerosis (ALS) and controls with or without neurologic diseases. By light microscopy, collagen bundles in ALS dermis were reduced in amount and more loosely woven than in controls. Electronmicroscopy revealed a significant negative correlation between duration of illness and the diameter of collagen fibrils in patients with ALS. There was also a marked increase of amorphous material positive for ruthenium red in the ground substance. These findings were not observed in controls.