• skin rash - usually throughout the body with both flat and raised patches which may involve the palms and soles
• enlarged lymph nodes
• mucous patches (painless silvery ulcerations of mucous membranes -- seen mostly in the mouth and on the genitals)
• condyloma lata: coalescing papules which form a grey-white plaque frequently in folds such as groin, genital areas, axilla and under the breasts
• hair loss (alopecia)
• general symptoms such as fever, fatigue, loss of appetite, aches and pains in bones, achy muscles, and achy joints
• in a few cases of secondary syphilis, the original chancre may still be present

The diagnosis of secondary syphilis is usually based on blood tests. An initial screening is done with the non-treponemal tests such as VDRL or RPR. If these are positive, the diagnosis is confirmed by another blood test for a specific antibody - the FTA-ABS fluorescent treponemal antibody test.

In addition to blood tests, if skin or mucous membrane lesions are present, the organism which causes syphilis may be identified on darkfield microscopic examination.