Atypical EM with previous misdiagnosis and treatment failure. A 26 year old woman was diagnosed with a brown recluse spider bite and treated with oral cephalexin and prednisone for an erythematous lesion with a central eschar (panel A). Ten days later, she has persistent malaise and generalized aches and was seen by one of the authors (JA). She was found to have healing of the primary EM lesion with the appearance of new secondary lesions (panel B). Serology showed ELISA reactivity with positive confirmatory IgM and IgG western blots. Treatment with oral doxycycline resulted in a prompt response and resolution of the lesions and symptoms.