Acrodermatitis chronica atrophicans: histopathologic findings and clinical correlations in 111 cases.

We studied 111 consecutive, untreated and serologically confirmed patients with acrodermatitis chronica atrophicans. Emphasis was on the histopathologic patterns of erythematous and fibrous lesions, and on an assay used to correlate histopathologic findings with such clinical features as fibrous nodules, ulnar bands and the pain reaction allodynia. There was a significant correlation between allodynia and signs of marked inflammation, but not between allodynia and neural and perineural cell infiltrates or fibrosis. Moreover, there was no significant correlation between serum IgG titers to Borrelia and the density of inflammatory cell infiltrates or the proportion of plasma cells in tissue. Histopathologic examination did not reveal any important differences between fibrous nodules, ulnar bands and sclerodermatous lesions. The histopathologic pattern is not diagnostic per se, but characteristic enough to alert the experienced pathologist.