Signs and Symptoms of Syphilis

STD Linked to Higher Rates of HIV Infection

Robert Sumpter/CDC

Sexually transmitted diseases (STDs),  are among the most common causes of illness in the world. In some populations, STDs like syphilis, gonorrhea, and chlamydia are at epidemic levels.

Syphilis is known to increase the risk of HIV as the open sores caused by infection provide an ideal portal for the virus to enter the body. Moreover, an active syphilis infection can increase the level of virus in genital secretion, increasing the chances that the virus will be passed to others.

Facts About Syphilis

Syphilis was first described in the 16th century, where it was often called the "Great Imitator" for its ability to resemble other common infections and diseases. Industrialized countries, such as the United States, saw a decline in syphilis during the latter half of the 19th century, which dropped even further with the advent of antibiotics and diagnostic technologies.

Since the late 1960s the incidence of syphilis has risen steadily again. Today, there are more 36,000 new cases of syphilis in the U.S. each year, with rising rates among key HIV populations, including African Americans and men who have sex with men (MSM).

How Do People Get Syphilis?

Syphilis is caused by a bacteria known as Treponema pallidum. The spirochete is passed from person to person almost exclusively through oral, anal, or vaginal sex.

The primary symptom of syphilis is a painless ulcer known as a chancre, which occurs in an area that has been exposed to the bacteria (primarily the penis, anus, vagina, and throat).

Contact with a chancre during sex allows for transfer of the spirochete from one person to another. Once in the blood stream, syphilis multiplies and, if left untreated, can even disseminate into the cerebral spinal fluid and brain.

What Are the Symptoms of Syphilis?

In the early stages of infection, people with syphilis can go for years without symptoms at all.

In many cases, the open sores (chancres) may go unnoticed, particularly in the rectum or vagina. The chancre will heal on its own over the course of a few weeks, but about 25 percent of people with untreated syphilis will experience other symptoms such as a rash, fever, and swollen lymph nodes.

The stages and symptomatology of syphilis is typically defined in three parts:

Primary Infection

During primary stage infection, a single sore (chancre) erupts on the penis, vagina, or anus. Usually this occurs anywhere from 10 to 90 days after infection. The round painless sore typically appears at the point where syphilis entered the body.

The sore will last from three to six weeks and heals without treatment. Often, the chancre goes unnoticed and therefore the infection goes untreated. However, if a syphilis chancre is identified, treatment is strongly suggested because without it, syphilis will progress to the secondary stage.

Secondary Infection

The secondary stage of syphilis is characterized by a period of latency, where symptoms may or many not be apparent or may resolve on their own without incident. Some of the more common secondary state symptoms include:

  • mucous membrane lesions
  • a red, non-itching rash on the palms of the hands and soles of the feet
  • fever
  • swollen lymph nodes
  • sore throat
  • hair loss
  • weight loss
  • muscle aches
  • fatigue

As with primary infection, secondary infection, if left untreated, can progress to more serious manifestations of disease.

Tertiary Infection

Tertiary infection is often referred to as the "hidden stage" since any of the outward signs of secondary infection will have largely resolved. It's at this stage that untreated syphilis can cause damage to internal organs, the central nervous system, and to bones and joints. In some cases, if treatment is not sought, late stage syphilis can be fatal.

How Is Syphilis Treated?

The treatment of choice for syphilis in any stage is the antibiotic penicillin.

A single injection of penicillin can prevent syphilis from progressing to later stages if the infection is less than a year old.

After one year, treatment consists of three intramuscular penicillin injections given one week apart. In the case of late syphilis or neurosyphilis (syphilis in the central nervous system), several weeks of intravenous penicillin is required.

Prevention and Control of Syphilis

Syphilis is a classic example of a sexually transmitted disease that can be successfully controlled by employing a few prevention measures:

  • Regular syphilis testing, especially in high risk populations to allow for early diagnosis and treatment. Rapid testing is also now available.
  • Treat all stages of syphilis with penicillin (or other appropriate antibiotics for those allergic to penicillin).
  • Use condoms or dental dams when engaging in sex, particularly if your partner is of unknown status or if you engage in multiple partners.

It's important to note, however, that while the HIV prevention pill (PrEP) may be effective in reducing your risk of acquiring HIV, it does not reduce your risk of getting any other sexually transmitted infection. As such, consistent condom use is still consider the front line tool in reducing personal risk. 


Centers for Disease Control and Prevention. "2015 Sexually Transmitted Diseases Treatment Guidelines - Syphilis." Atlanta, Georgia; accessed May 27, 2016.