Syphilis on the Rise: What You Need to Know

The number of cases of syphilis in the US has reached its highest level since 1995, more than doubling in just the past 10 years. The vast majority of cases–over 90 percent–are occurring in men with same-sex partners, while infection rates in women are actually decreasing. Last year, over 16,000 cases were reported, but due to underreporting, this is probably an underestimate of the true size of the epidemic. A major cause of this increase is the declining use of condoms by people who are at risk.

This epidemic is troubling not only because the disease itself can be so devastating if left untreated, but because syphilis and the sexual behaviors associated with it increase the chances of acquiring and transmitting HIV–the co-infection rate is as high as 70 percent. And no, HIV preventive therapy with Truvada does not protect against syphilis.

Here are some important things you need to know about this STD:

Syphilis is caused by a bacterium called Treponema pallidum. It enters the body through tiny abrasions, almost always during sexual intercourse. Rarely, it’s contracted by contact with other infectious lesions of the skin and mucous membranes, or in utero during delivery.

Typically, the initial lesion is a sore called a chancre that appears at the site of inoculation approximately three weeks after infection. It can be large and dramatic or a small, barely noticeable papule. The chancre is painless and soon erodes to form a shallow ulcer. Some people develop multiple chancres. Chancres heal within several weeks, even without treatment, but the infection remains alive in the body and quickly spreads.

Within several weeks to months, if the initial lesion is untreated, a person may develop flu-like symptoms–headache, sore throat, muscle and joint aches, swollen lymph nodes, and a low-grade fever. A rash will typically develop, covering much of the mucous membranes and skin, particularly on the palms and soles of the feet.

Most people seek medical attention at this point, but if left untreated, the disease enters a long latent period during which there are no clinical signs or symptoms at all. Anywhere from one to as many as 30 years later, a person may enter late-stage syphilis, which can affect any organ in the body–potentially causing severe damage to the heart, aorta, and brain.

There are several methods for diagnosis, but the most common is a blood test that screens for the infection.

Penicillin has been an effective treatment for syphilis at all stages without any signs of treponemes developing a resistance to it. The intensity and duration of treatment varies depending on the advancement of the disease. For patients allergic to penicillin, there are acceptable alternatives.

There is no vaccine for syphilis. The best way to prevent the disease is to follow safe sexual practices–most importantly, using condoms. Partners of an infected person who have been exposed within 90 days should be treated as if they have the disease, even if their blood tests are negative. And all infected people and their partners should also be tested for HIV infection.