Background: Acrodermatitis chronica atrophicans (ACA) is a late manifestation of infection caused by Borrelia burgdorferi.
Objective: Our purpose was to study the clinical, histopathologic, and immunohistochemical findings in patients with ACA to understand better the pathogenesis of the disease.
Methods: Five patients were studied. Skin biopsy specimens were obtained from active lesions for histologic and immunohistochemical studies.
Results: Clinical lesions included an initial erythematous discoloration in one patient and violaceous infiltrated plaques and nodules in four patients, three of whom also had late atrophic lesions. Biopsy specimens showed a dermal perivascular and interstitial lymphocytic infiltrate with plasma cells. There was a predominance of CD3+, CD4+ T cells in the dermal infiltrate. B cells were present in three patients. The dermal infiltrate showed an intense expression of lymphocyte function-associated antigen. The intercellular adhesion molecule type 1 was expressed on endothelial cells, perivascular mononuclear cells, and focally on basal keratinocytes.
Conclusion: Our findings suggest that a chronic, T-cell-mediated immune reaction against B. burgdorferi is involved in the pathogenesis of ACA.