Background: Acrodermatitis chronica atrophicans is a delayed manifestation of Lyme disease caused by a Borrelia burgdorferi subspecies, B. afzelii. Although rheumatic manifestations are rare, they can result in deformities of the fingers and toes if they are not treated promptly.
Methods: We report four cases of acrodermatitis chronica atrophicans seen over a 15-year period.
Results: Two patients had a noninflammatory unilateral knee effusion and one had swelling of the dorsum of one hand. Antimicrobial therapy was followed by a full recovery in the three patients who received an early diagnosis. The remaining patient, a 63-year-old woman, had swelling and dysesthesia in the fingers of both hands. She developed finger deformities over a period of two years. Although the swelling resolved under antimicrobial therapy, she had persistent reducible deformities of the fingers consistent with Jaccoud's arthropathy.
Conclusion: The diagnosis of acrodermatitis chronica atrophicans rests on a history of a tick bite, a suggestive skin biopsy histology and a positive Western blot for B. afzelii. A positive response to antimicrobial therapy is also required. Acrodermatitis chronica atrophicans, a common condition in central and northern Europe, can cause joint manifestations and persistent finger deformities in the absence of early treatment.