Acrodermatitis chronica atrophicans

Overview
Acrodermatitis chronica atrophicans (ACA) also known as Pick-Herxheimer disease, 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.

This progressive skin process is due to the effect of continuing active infection with the spirochete Borrelia afzelii. B afzelii is the predominant pathophysiology, but may not be the exclusive, etiologic agent of ACA. Borrelia garinii, has also been detected.

History
The first record of ACA was made in 1883 in Breslau, Germany, where a physician named Alfred Buchwald first delineated it.

Herxheimer and Hartmann described it in 1902 as a "tissue paper" like cutaneous atrophy.

Presentation
The rash caused by ACA is most evident on the extremities or limbs beginning with an inflammatory stage with bluish red discoloration and cutaneous swelling and concluding several months or years later with an atrophic phase. Sclerotic skin plaques may also develop.

As ACA progresses the skin begins to wrinkle.

Prognosis and Treatment
The course of ACA is long-standing, from a few to several years, and it leads to extensive atrophy of the skin and, in some patients, to the limitation of upper and lower limb joint mobility.

The outlook is good if the acute inflammatory stage of ACA is treated adequately. The therapeutic outcome is difficult to assess in patients with the chronic atrophic phase, in which many changes are only partially reversible.

Physicians should use serologic and histologic examination to confirm the diagnosis of ACA. Treatment consists of antibiotics including doxycycline and penicillin for up to four weeks in the acute case.