Syphilis, the main sexually transmitted disease, has an increasing incidence especially among people who have sexual contact with people of the same gender.

Clinical manifestations of syphilis can be varied: thus, within the primary stage there occur mucocutaneous and ganglionar lesions accompanied in the secondary and tertiary stage of the disease, by disseminated mucocutaneous syphilides and multiple organ manifestations. In secondary syphilis, syphilides can take particular clinical aspects (psoriasiform, acneiform, seborrheic etc.), that may pose problems of differential diagnosis. Early and accurate diagnosis, with disease epidemiological chain termination, is a priority in the management of syphilis. We present a patient with psoriasis vulgaris who raised problems of differential diagnosis due to the simultaneous presence of psoriasis-like syphilides.

Corroborating clinical data (muco-cutaneous) with epidemiological and serological data allowed setting up the accurate diagnosis of secondary syphilis associated with a flare of guttate psoriasis.