Serologic follow-up examinations are frequently performed in patients with erythema migrans, borrelial lymphocytoma, and acrodermatitis chronica atrophicans (the 3 dermatoborrelioses) to evaluate treatment efficacy. There is, however, substantial proof in the literature that antibody titer development after therapy is unpredictable and variable, and moreover it is largely uncorrelated with the clinical course and mode of antibiotic treatment. For example, persistent positive IgG and/ or IgM antibody titers do not indicate treatment failure. Thus, repeated serologic testing is of very limited value for assessing therapy efficacy, and therefore not recommended in the follow-up of dermatoborrelioses patients. Since cultivation of the etiologic agent, Borrelia burgdorferi sensu lato, and polymerase chain reaction are also inadequate for this purpose, the assessment of patients with cutaneous manifestations of Lyme borreliosis in the follow-up rests primarily on the clinical picture.