Acrodermatitis chronica atrophicans

Acrodermatitis chronica atrophicans (ACA) (also known as "Herxheimer disease" and "Primary diffuse atrophy") is a skin rash indicative of the third or late stage of European Lyme borreliosis.

ACA is a dermatological condition that takes a chronically progressive course and finally leads to a widespread atrophy of the skin. Involvement of the peripheral nervous system is often observed, specifically polyneuropathy.