Skin involvement in amyotrophic lateral sclerosis

Background Patients with sporadic amyotrophic lateral sclerosis (ALS) show disorganised collagen and elastin of the dermis. We looked for inflammatory alterations to cutaneous blood vessels. Patients and findings Seven patients with sporadic ALS were investigated; five were confined to bed, but none had bedsores. Light and electron microscopy of skin showed an oedematous dermis with collagen fibrils of irregular diameter. Small blood vessels were characterised by duplicated basement membranes and deposition of beta-amyloid protein, the main component of the neuronal and non-neuronal amyloid deposits in Alzheimer's disease. These skin changes were seen in all degrees of disability, but none was found in age-matched and sex-matched controls. Interpretation The skin in ALS is characterised by a distinctive pattern of alterations of connective tissue and blood vessels. Examination of skin is an additional and easily accessible investigation which may help elucidate the pathogenesis of ALS.