Acrodermatitis chronica atrophicans (ACA). Acrodermatitis chronica atrophicans (ACA) is a skin manifestation in the late phase of borrelial infection. This elderly female patient had skin atrophy on the back of her right hand. The patient had typical histopathological features and positive IgG borrelial serum antibodies, and borrelial DNA was found in a PCR study of the lesional biopsy specimen. Atrophy was reversed to some degree after appropriate antibiotic therapy.

Picture: Raimo Suhonen