Syphilis is a sexually-transmitted infectious disease caused by the spirochete Treponema pallidum. Syphilis has three main stages: primary syphilis, secondary syphilis, and tertiary syphilis.

Approximately one-third of untreated individuals with primary syphilis will progress to the second stage: secondary syphilis. This usually occurs at about 2 to 8 weeks after the appearance of the original painless sore (chancre) and in some cases the chancre may still be present.

In secondary syphilis, the bacteria have spread in the bloodstream and have reached their highest numbers. The most common symptoms include skin rash, which can be varied in appearance, yet frequently involves the palms and soles, in addition to lesions in the mouth, vagina or penis, called mucous patches. Other lesions that can appear are moist, warty patches on the genitalia or skin folds called condylomata lata.

During secondary syphilis, additional symptoms such as fever, malaise, loss of appetite, and swollen lymph nodes may also be noted. This stage is the most contagious stage of syphilis. While it usually resolves within weeks, in some cases it may last up to a year.

• 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.

The mainstay of treatment of secondary syphilis is antibiotic therapy. The antibiotic of choice is penicillin (which is usually given by injection once a week for three weeks). In individuals allergic to penicillin, doxycycline may be used for a total of two weeks.

After antibiotic treatment, follow-up blood tests (RPR) should be done at 3 and 6 months (and later if needed) to assess whether treatment was effective, as treatment may need to be repeated or additional evaluation performed.

In some individuals, a Jarish-Herxheimer reaction may occur several hours following treatment of secondary syphilis. This is characterized by fevers, chills, malaise, joint and muscle aches, and usually lasts 24 hours.

The complications of syphilis are related to the development of the syndromes associated with tertiary syphilis:

• neurosyphilis
• cardiovascular complications (aortitis and aneurysms)
• destructive lesions of the skin and bones (gummas).

In addition, untreated secondary syphilis during pregnancy may result in transmission to the fetus (congenital syphilis).