Secondary syphilis Because syphilis can mimic many diseases, it should be considered when any cutaneous eruption or mucosal lesion is undiagnosed, particularly if patients have any of the following: Generalized lymphadenopathy Lesions on the palms or soles Condyloma lata Risk factors (eg, HIV, multiple sex partners) Clinically, secondary syphilis may be mistaken for a medication eruption, rubella, infectious mononucleosis, erythema multiforme, pityriasis rubra pilaris, fungal infection, or, particularly, pityriasis rosea.