Medically reviewed on February 15, 2022 by Jordan Stachel, M.S., RDN, CPT. Last updated October 2, 2023. 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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There are over 35 infectious organisms known to cause sexually transmitted diseases. While many STDs are largely preventable or treatable, they remain a huge burden and a significant health issue in the country. On top of medical costs and complications, many STDs can lead to serious, long-term health issues, including reproductive health problems, increased risk of certain cancers, and fetal and/or perinatal problems .
Syphilis and herpes are two of the most common STDs in the United States, but they can be easy to mistake or miss. While a herpes or syphilis test can help you know which STD you might have, it’s important to understand the differences between the two infections. Learn more about syphilis and herpes and how you can tell the difference.
Syphilis is a bacterial infection spread primarily via sexual skin-to-skin contact, though mothers can also pass the infection to a child during birth . It is noted for the appearance of sores, known as chancres, and can be transmitted when skin or mucus membranes make contact with these sores. While early syphilis can be cured, this infection can stay in the body for decades following the initial infection.
So what does syphilis look like? There are four stages to a syphilis infection, often associated with distinct physical signs:
Primary stage – The first stage of syphilis infection is often characterized by a small, painless sore, known as a chancre, where the infection entered your body.
Secondary stage – Usually, the secondary stage of syphilis is accompanied by a red or reddish-brown rash, with or without the continued presence of geneital sores. The rash is usually not itchy, but it can be accompanied by the appearance of genital warts and canker sores in the mouth. You may also experience general flu-like symptoms, like fever, sore throat, muscle aches, and swollen lymph nodes. These symptoms can go away after a few weeks, but they can repeatedly come and go for up to two years.
Latent stage – This stage is marked by the absence of noticeable symptoms. However, this doesn’t mean that the infection has gone away.
Tertiary stage – Without treatment, the sexually transmitted infection will stay in the system and proceed to the final stage of syphilis. Late stages of syphilis can lead to serious health issues, such as organ damage, heart issues, and damage to the brain and nervous system.
Herpes is an infection caused by two viruses: herpes simplex virus 1 (HSV-1) and herpes simplex virus 2 (HSV-2) . The infections are differentiated as follows:
HSV-1 – This strain of the herpes virus is responsible for oral herpes, such as fever blisters or cold sores in or near the mouth. Often, HSV-1 doesn’t present symptoms and is frequently transmitted via non-sexual contact with the saliva of a person with the herpes simplex virus.
HSV-2 – Commonly known as genital herpes, you can only contract this strain of the herpes virus by direct contact with the genitals of someone infected.
It is possible to transmit HSV-1, oral herpes, to the genital region via oral sex. It’s also important to know that herpes can spread even in the absence of visible sores. Treatment can help minimize or in some cases prevent herpes outbreaks and can help reduce the risk of passing the virus along to sexual partners.
Herpes is extremely common. Estimates suggest that half of Americans have oral herpes, while roughly 1 out of every 6 Americans has genital herpes. Part of this comes from just how easily the virus spreads. While it is an STD, herpes does not require sex for transmission. Simply contacting an open sore is enough to transmit it from person to person. This becomes even easier given that many people don’t know that they have herpes, as sores can easily be mistaken for other skin conditions.
There is also no cure for herpes (though treatments exist for symptom management), meaning that you can have it for life and not know it. Herpes is thankfully not dangerous or life-threatening to the average, healthy individual, but sores can be uncomfortable and painful.
Syphilis and herpes can often seem similar to the average person. Both are characterized by skin lesions or sores that can appear on the genitals, rectum, or around the mouth. However, these sores are significantly different in how they look and feel.
Key differences between syphilis and herpes include:
Incubation period – The incubation period refers to the amount of time it takes for an infection to exhibit symptoms after it enters your body. According to the Centers for Disease Control (CDC), herpes symptoms typically appear within 2–4 days of infection but can take up to 12 days. Syphilis symptoms typically appear 21 days after infection, although it can take as long as three months.
Sore size, texture, and pain – Although they can appear similar, they differ in size, texture, and pain severity. According to the CDC, herpes sores are small with a diameter of about 1–3 millimeters. They may appear as blisters and can be quite painful. Syphilis sores can be up to three centimeters in size, are painless, and feel hard to the touch.
Amount of sores – Typically, syphilis will present as a single sore. Herpes, on the other hand, can present as a group of small sores or blisters, according to the CDC.
Time to heal – Herpes sores typically clear up in a couple of weeks, although they can take as long as one month. Syphilis sores can take longer, up to eight weeks in some cases. After healing, syphilis sores may leave scarring on the skin.
You can also look at other symptoms to tell these two infections apart. Both can potentially cause flu-like symptoms. This occurs with secondary syphilis and with forms of genital herpes caused by HSV-2. However, genital herpes outbreaks can also come with other pain and discomfort around the genitals, including:
Syphilis usually does not cause these uncomfortable symptoms in the genitals. On the other hand, secondary syphilis can cause a rash that spreads throughout the entire body, which is not what herpes does.
It’s also important to understand the potential complications involved. As mentioned, herpes can be deeply uncomfortable and painful with each outbreak, and it can have some serious effects on relationships. However, it is mostly harmless and doesn’t present any real danger to most healthy adults. Symptoms can potentially be more painful and last longer in those with suppressed immunities, like those with HIV or leukemia, and herpes infection can also be potentially dangerous to newborn babies.
Syphilis presents some serious dangers for not only sexual health, but also overall well-being. Left untreated, a syphilis infection can progress to the point where it causes severe damage to the nervous system, bones, joints, blood vessels, and major organs. It can damage the eyes and contribute to vision loss. Serious cases of syphilis can be deadly.
Syphilis is easy to treat in its early stages with a round of antibiotics, allowing you to cure the infection completely. Even in its later stages, antibiotics can cure the infection and prevent continued damage to the body (though they can’t reverse or heal existing damage).
Currently, herpes cannot be cured, but medication can reduce the severity and length of outbreaks or even prevent outbreaks from happening at all. This is known as suppressive therapy, and it can be highly effective in even preventing the spread of herpes to your sexual partners .
While syphilis and herpes are completely different STIs, they do share one significant thing: they are both easy to miss. Both STDs can present a few noticeable symptoms or symptoms that are easy to mistake for other skin conditions. This is partly why they spread so easily among sexual partners. A good way to prevent the spread of both STDs is to practice safe sex. Use condoms and other protective devices every time you have sex.
Along with safe sex, make sure you get tested for STDs. Testing allows you to catch infections before they become severe and allows for proactive management of personal health. If you don’t have access to a clinic or simply want to take a test in the comfort of your own home, Everlywell offers convenient STD tests: the at-home STD Test - Female and STD Test - Male. These tests offer accurate results for seven common STDs: chlamydia, gonorrhea, hepatitis C, herpes simplex virus type 2 (HSV-2), HIV, syphilis, and trichomoniasis. If your tests come back positive, we can connect you with a healthcare provider to determine the next steps for better health.