Secondary syphilis: Introduction. Secondary syphilis: A condition which is characterized by fever, multiform skin eruptions, iritis, alopecia, mucous patches and severe pain in the head and joints. More detailed information about the symptoms, causes, and treatments of Secondary syphilis is available below.econdary syphilis: Introduction. Secondary syphilis: A condition which is characterized by fever, multiform skin eruptions, iritis, alopecia, mucous patches and severe pain in the head and joints. More detailed information about the symptoms, causes, and treatments of Secondary syphilis is available below.