Acrodermatitis chronica atrophicans--a spirochetosis. Clinical and histopathological picture based on 32 patients; course and relationship to erythema chronicum migrans Afzelius.

The recent discovery that spirochetes transmitted by the tick Ixodes ricinus are involved in the etiology of erythema chronicum migrans Afzelius (ECMA), Bannwarth's syndrome, and acrodermatitis chronica atrophicans (ACA) has thrown new light upon these disorders. Thirty-two patients showing clinical and serological evidence of ACA were investigated. Histologically, constant findings in active ACA lesions were telangiectases and a lymphocytic infiltrate with a moderate to rich admixture of plasma cells. Clinically, besides ACA lesions, lichen sclerosus et atrophicus (LSA)-like lesions were found in five patients. Four of these patients displayed a histopathological picture compatible with LSA. These findings suggest a relationship between ACA and LSA. In six patients spontaneous healing of ECMA was followed by ACA lesions after a latency period of 1-8 years. Six patients reported histories of cranial nerve involvement. Radiography revealed subluxation of joints in hands or feet in six patients, and periosteal thickening in another three patients. The results indicate that ACA may be a late manifestation of infection with the same spirochete that causes ECMA and Bannwarth's syndrome. If untreated, the infection may continue for many years and result in irreversible degenerative lesions.