RESUMEN
BACKGROUND: Morphea and lichen sclerosus et atrophicus (LSA) are sclerotic skin lesions of unknown etiology involving connective tissue. The hypothesis of a borrelial origin of morphea and LSA is currently controversial. METHODS: Immunoglobulin G (IgG) immunoblot serologies against Borrelia burgdorferi in patients with morphea and LSA were analyzed and compared with those from healthy donors and patients with syphilis to determine the association with a probable borrelial agent in Colombia. RESULTS: No significant differences in the number of reactive antigenic bands were found between morphea/LSA patients and syphilis patients or healthy donors. The presence of at least one of the following bands, p28, p39, or p45, was the criterion most able to distinguish morphea/LSA, yielding a specificity of 95% and a sensitivity of 28.6%. Using this criterion as evidence of putative exposure to a causative borrelial agent, sclerotic skin lesions had an odds ratio of 7.60 (95% confidence interval, 1.47-39.23). CONCLUSIONS: These results could be explained by cross-reactivity; however, the partial shared reactivity of sera from patients with syphilis and morphea/LSA does not rule out the possibility that a new spirochetal agent, unrelated to B. burgdorferi or Treponemas, may be the causative agent of morphea/LSA in Colombia.