Chlamydia, Gonorrhea, Syphilis, or Herpes? How to Tell the Difference

Bacteria and viruses can be spread during intimate physical contact, leading to over 20 million new cases of sexually transmitted infections (STIs) every year. Chlamydia, gonorrhea, syphilis, and genital herpes are among the most common and well-known STIs. But there are significant differences between them, from how they show up to how they’re treated.

Sometimes your symptoms point to a specific STI, but proper testing is still essential because a clear diagnosis enables effective treatment. If you have an STI, testing your sex partner, too, can help you both receive prompt treatment and reduce the risk of reinfections.

This guide covers key information about common STIs, including their tell-tale signs, possible complications, and standard treatments.

Common STIs

Chlamydia vs. Gonorrhea

Chlamydia and gonorrhea can be hard to tell apart because both are bacterial infections that present with similar symptoms. It’s also possible to have both gonorrhea and chlamydia at the same time. 

Symptoms of gonorrhea and chlamydia in women and men include abnormal discharge, painful urination, and an increased need to urinate. Given their similarities, doctors often test for these two STIs together. Testing can pinpoint which infection you have so you get the right treatment.

Chlamydia

Chlamydia is the most commonly reported STI in the United States. It is caused by an infection with the Chlamydia trachomatis bacteria. Chlamydia spreads during sexual contact, including vaginal, anal, or oral sex. Chlamydia can also spread without sex. The most common non-sexual route is from mother to baby during childbirth, which can cause eye infections or pneumonia in the newborn. Less often, the bacteria can reach the eye from hands contaminated with the bacteria.

What Does Chlamydia Look Like?

Chlamydia doesn’t usually cause sores. Instead, the clearest visual sign is abnormal discharge from the vagina, penis, or rectum. The other most common symptoms of chlamydia include: 

• Yellow, white, or cloudy gray discharge from the vagina
• Clear or cloudy discharge from the penis
• Yellowish discharge from the anus
• Burning or pain when urinating
• Increased need to urinate
• Redness at the opening of the penis
• For women, pelvic pain and/or pain during sex
• Rectal pain or bleeding

If the infection gets worse, it may cause additional symptoms, such as fever, nausea, abdominal pain in women, and testicular swelling and pain in men. When it affects the mouth or throat, chlamydia normally doesn’t cause symptoms, though in rare cases it may cause pain or bumps to form on the tongue.

Complications of Untreated Chlamydia

If left untreated, chlamydia infections can become more painful and spread to other parts of the body. They can cause eye problems and a painful joint condition called reactive arthritis.

In women, chlamydia can spread through the abdomen, pelvis, and reproductive tract. Untreated chlamydia can damage the fallopian tubes and cause pelvic inflammatory disease (PID), which can result in significant pain, infertility, and a higher risk of ectopic pregnancy.

In men, untreated chlamydia can cause a narrowing of the urethra and painful swelling of the testicles (epididymitis) that may lead to infertility.

H4: Chlamydia Treatments
Chlamydia is very treatable with antibiotics. Most chlamydia cases are prescribed a one-week course of doxycycline (Vibramycin) as the standard initial treatment. Other antibiotics may be prescribed based on your specific situation, such as if you also have gonorrhea or another STI at the same time.

Gonorrhea

Gonorrhea is an STI caused by the Neisseria gonorrhoeae bacteria. It is spread during oral, vaginal, or anal sex. It can also spread in non-sexual ways, such as from a mother to her baby during childbirth or from bacteria-contaminated hands to the eyes. 

Gonorrhea infections typically occur in the genitals, rectum, or throat, but the infection can spread to other parts of the body.

What Does Gonorrhea Look Like?

The most visible sign of gonorrhea is an abnormal yellow or yellow-green discharge from the penis, vagina, or anus. Gonorrhea does not usually look like sores or lesions. The other most common symptoms of gonorrhea include:

• Pain during urination
• Increased need to urinate
• For women, pain around the vagina
• For men, redness or irritation around the opening of the penis

More extensive spread of gonorrhea can cause additional symptoms, including abdominal pain, bleeding after sex (in women), rash, and fever. Gonorrhea can infect the throat, but other than the occasional sore throat, it may not show other symptoms.

Complications of Untreated Gonorrhea

Without treatment, gonorrhea can extend to different parts of the body. In women, it can cause pelvic inflammatory disease after reaching the uterus, cervix, fallopian tubes, ovaries, and inner lining of the abdomen. In some cases, this leads to infertility or complications during pregnancy.

In men, untreated gonorrhea can impact the testicles, causing painful swelling (epididymitis). It may also result in abscesses, scarring, or narrowing of the urethra. 

In both men and women, the infection can spread to the eyes. More rarely, untreated gonorrhea can impact the joints, heart valves, or area around the brain (meningitis).

Gonorrhea Treatments

Antibiotics are the principal treatment for gonorrhea. In many cases, a single injection of ceftriaxone (Rocephin) is effective. When an injection isn’t an option, some oral antibiotics like cefixime (Suprax) may be prescribed. In December 2025, the FDA approved two new oral antibiotics for gonorrhea that affects the genitals or urethra. 

For more severe infections, you may have to stay at the hospital to receive intravenous (IV) antibiotics. More than one antibiotic may be suggested if you have a dual infection with gonorrhea and chlamydia.

Syphilis vs. Herpes

Syphilis and herpes sometimes get confused because both are STIs that cause visible sores. They can also trigger bumps or rashes in the mouth and throat that may be hard to detect. 

That said, there are key differences. Syphilis is caused by bacteria, while herpes is a viral infection. Syphilis bumps (chancres) are typically painless in the early stages. In contrast, herpes blisters tend to cause mild to severe pain. In addition, syphilis is curable, but herpes is a chronic, lifelong infection with recurring outbreaks. There’s no cure for herpes, though symptoms can be managed.

Syphilis

Syphilis is caused by the bacterium Treponema pallidum. It spreads primarily through sexual contact, but a few other routes are possible. Syphilis can spread via direct skin contact with a sore, such as by kissing someone with an oral chancre. It can also be transmitted to a fetus during pregnancy.

Syphilis infections can progress through four stages:

• Primary
• Secondary
• Latent
• Tertiary

Symptoms and complications become more severe in each stage.

What Does Syphilis Look Like?

Syphilis starts with a small, red, and painless sore called a chancre. The sore may become raised and change to a gray or yellow color. These signs of syphilis are similar in women and men. Syphilis sores are most often found on the genitals, but they may also appear on the mouth, rectum, or skin. Depending on their location, the sores may go unnoticed. In primary syphilis, lymph nodes near a chancre may be swollen or tender.

The sore normally heals on its own within a few weeks, but that doesn’t mean the infection is gone. Without treatment, syphilis can still progress after a period without symptoms. If treated early, symptoms usually stop here.

In secondary syphilis, the infection gets into the bloodstream, which can cause more extensive symptoms, including: 

• “Copper penny” rashes, usually on the palms of the hands and soles of the feet
• Raised growths or patches in the mouth, genitals, armpits, or other places where the skin is moist
• Swollen lymph nodes
• Hair loss from sores on the scalp
• Fever and chills
• Fatigue
• Appetite loss
• Eye inflammation and vision problems
• Joint, muscle, or bone pain
• Abdominal pain
• Jaundice
• Headaches

Not everyone with secondary syphilis has all of these issues, and symptoms may vary depending on where the infection spreads. 

Complications of Untreated Syphilis

Untreated syphilis can be life-threatening. If secondary syphilis goes unaddressed, it may progress to tertiary syphilis (the third stage). At this point, the infection can impact the heart, brain, and spinal cord. 

When it occurs, tertiary syphilis raises the risk for heart failure and aneurysms in the aorta. If syphilis reaches the central nervous system, it can cause mood changes, strokes, paralysis, tremors, and intense pain. Fortunately, because of the availability of testing and treatment, tertiary syphilis is uncommon in the United States.

Syphilis Treatments

Syphilis is typically treated with a single injection of penicillin. An oral antibiotic, such as doxycycline, may be prescribed for people who can’t take penicillin. In more advanced cases of syphilis, more than one injection or a course of IV antibiotics may be necessary to treat the infection.

Herpes

Genital herpes is a viral infection that causes blisters on or around the genitals, mouth, or anus. The herpes simplex virus type 2 (HSV-2) causes most cases. Genital herpes spreads through sexual activity and skin-to-skin contact. It can spread from skin and bodily fluids, including when no blisters are visible. Non-sexual transmission can occur from a mother to a baby when giving birth. 

There’s no cure for HSV-2, but the symptoms can be managed. After an initial infection, the virus remains dormant in the body and can flare up intermittently. Treatments are available to shorten these outbreaks and ease symptoms

What Does Herpes Look Like? 

Genital herpes typically begins as a cluster of small blisters, which can break open into painful sores. Blisters can appear near the genitals or anus, or inside the vagina or rectum where they are more difficult to see.

Other symptoms that may occur, especially during an initial herpes infection, include:

• Fever
• Body aches
• Swollen lymph nodes
• Headache
• Pain when urinating
• Difficulty urinating
• Constipation
• Abnormal vaginal or penile discharge

During herpes outbreaks after an initial infection, symptoms are usually mild. Before blisters appear, you may feel pain or tingling in the genitals or groin.

It is possible to have herpes in the throat, but that’s usually caused by a different strain of the herpes virus, called herpes simplex virus type 1 (HSV-1).

Complications of Untreated Herpes

Even if left untreated, herpes does not usually cause severe complications. But without treatment, symptoms may last longer and be more bothersome. Though rare, herpes can spread to other parts of the body, including the eyes, internal organs, and the brain.

Herpes Treatments

Herpes can be treated with oral antiviral medications that make symptoms less severe and go away more quickly. Examples of antiviral herpes treatments include:

• Valacyclovir (Valtrex)
• Acyclovir (Zovirax)
• Famciclovir (Famvir)

For an initial infection, antivirals are commonly prescribed for 7 to 10 days. For recurrences, the antiviral course may be between 1 and 5 days, depending on the drug and dosage. For people who have frequent outbreaks, doctors may prescribe daily antiviral therapy. This can reduce how often outbreaks happen and lower the risk of spreading the virus to a partner. 

Are STIs All Treated the Same Way?

Not all STIs are treated the same way. STIs are caused by different bacteria and viruses, and treatments are designed to work against specific ones. 

For example, antibiotics don’t work against viruses (like herpes), and antiviral drugs don’t work against bacterial infections (like chlamydia, gonorrhea, and syphilis). On top of that, the right antibiotic depends on the bacteria. For example, ceftriaxone is the typical treatment for gonorrhea, while doxycycline is the standard for chlamydia. 

Your Next Steps

Chlamydia, gonorrhea, syphilis, and herpes can cause some similar symptoms, but each one is different and needs its own treatment. 

Knowing how to spot key differences is helpful, but testing is the most reliable way to protect yourself and your partner. If you think you might have an STI, talk to your doctor. They can prescribe testing and treatment, if necessary, including for your partner. Acting quickly can prevent the spread of STIs and reduce the risk of long-term complications.

If you already know what STI you need treatment for, such as if your sexual partner has already been tested, you may find STI treatments online. Make sure you go through a reputable online pharmacy platform like TelyRx to avoid common pharmacy scams and ensure your medication is sourced from licensed pharmacies. Especially for those who are uninsured or who have high copays or deductibles, a cash-pay pharmacy platform like TelyRx can make finding STI treatments online much easier without sacrificing any safety or privacy.