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How Common Is Syphilis?

Medically reviewed on March 8, 2022 by Jordan Stachel, M.S., RDN, CPT. To give you technically accurate, evidence-based information, content published on the Everlywell blog is reviewed by credentialed professionals with expertise in medical and bioscience fields.

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If you’re sexually active, you may be wondering about the prevalence of certain sexually transmitted diseases (STDs) and infections. Some STDs, like the human papillomavirus, or HPV, are exceedingly common. According to the CDC, 43 million people were diagnosed with HPV in 2018 alone, making it the most common sexually transmitted infection in the United States [1].

But how common is syphilis?

The answer is: relatively common. In fact, syphilis infections have been on the rise in the United States in recent years: while the reported incidence of primary and secondary syphilis stood at 2.12 per 100,000 in 2000, by 2017 this number had climbed to 9.5 cases per 100,000 [2]. Here’s what you need to know about the rates of syphilis (to check for syphilis from the comfort of home, try the Everlywell at-home Syphilis Test).

The Prevalence of Syphilis

The rate of syphilis cases has increased over the past couple of decades. In fact, the CDC reports that in 2019, there were 129,813 new syphilis diagnoses in the United States [3]. This includes new diagnoses at all stages of infection.

For context, the number of new syphilis cases reported in 2019 was far greater than new HIV infections (37,968 new cases in 2019) but far less than the rate at which gonorrhea was detected (616,392 cases) according to that same CDC report [3].

How Is Syphilis Transmitted?

Treponema pallidum, the bacterium that causes syphilis, is transmitted through sexual contact with a syphilis sore or chancre during sex. Syphilis sores can appear in the vagina, on the penis, or in the anus and are painless, which can mean that without syphilis testing, an infected person may not even know they have it.

Syphilis bacteria can also be transmitted from mother to child during pregnancy, resulting in congenital syphilis. This frequently has serious consequences; possible outcomes include spontaneous abortion and late-term stillbirth [4], low birth weight, high cholesterol levels in the newborn, and more. Bone pain, severe eye disease, and other health consequences may develop later in childhood and into adulthood [5].

How to Tell If You Have Syphilis

The only way to know for certain whether you’ve contracted the sexually transmitted infection of syphilis is to get tested. Syphilis is treatable with antibiotics. However, untreated syphilis can lead to serious health complications that sometimes develop as much as 30 years after the initial infection.

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If you think you may have contracted syphilis, here are the following signs and symptoms:

  • Syphilis sores – Syphilis sores generally appear within eight weeks of infection. They are hard, round sores that can be up to three centimeters in diameter. In most cases, there may be only a single sore, although multiple sores can occur.
  • Skin rashes – If your infection has progressed to stage two, a non-itchy skin rash in a red or reddish-brown color may develop. The rash may appear on the back, arms, the palms of the hands, or the soles of the feet.
  • Skin lesions – In stage two, skin lesions on the palms of the hands and soles of the feet may also develop [6]. These lesions may appear darkly colored and are usually non-vesicular, meaning they don’t ooze pus or other fluids.

Syphilis sores, rashes, and lesions typically go away on their own. However, treatment with antibiotics is the only way to clear the infection from the system, regardless of your symptoms.

If you don’t seek medical treatment, syphilis can progress to its final stage. In this stage, severe bodily issues like organ damage, ocular impairment, cognitive troubles (such as memory loss), and/or other issues can present.

Test Yourself with Everlywell At-Home Lab Tests

Contracting syphilis or any sexually transmitted disease can be alarming. But getting regularly tested can help you make the right decisions about your own sexual health and prevent the spread of infections among other people.

The Everlywell at-home Syphilis Test is an easy and private way to test yourself for the infection from the comfort of your home. This sexual health test comes with everything you need to safely collect a sample. When you’re done, use the prepaid return shipping label to send your sample to a lab for testing. Your results will be made available for you digitally and, if positive, you can connect with a healthcare provider in our network to discuss treatment options.

Symptoms of Syphilis in Females

Signs of Syphilis in Men

What Does Syphilis Look Like?

Ingrown Hair vs. Herpes: What Are the Differences?


  1. STD Facts—HPV. Centers for Disease Control and Prevention. URL. Accessed March 8, 2022.
  2. Schmidt R, Carson PJ, Jansen RJ. Resurgence of Syphilis in the United States: An Assessment of Contributing Factors. Infect Dis (Auckl). Published 2019 Oct 16.
  3. STD Facts—Syphilis. Centers for Disease Control and Prevention. URL. Accessed March 8, 2022.
  4. De Santis M, De Luca C, Mappa I, et al. Syphilis Infection during pregnancy: fetal risks and clinical management. Infect Dis Obstet Gynecol. 2012;2012:430585.
  5. Congenital Syphilis. National Organization for Rare Disorders. URL. Accessed March 8, 2022.
  6. Klausner JD. The great imitator revealed: syphilis. Top Antivir Med. 2019;27(2):71-74.
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