Sexually Transmitted Infections That Are Curable

What to Know About Syphilis, Gonorrhea, Chlamydia, and Trichomoniasis

Table of Contents
View All
Table of Contents

While many sexually transmitted infections (STIs) are incurable, there are four that are completely curable: syphilis, gonorrhea, chlamydia, and trichomoniasis. Each is effectively treated with one or more doses of an antibiotic drug, taken either by mouth or given by injection.

Despite effective treatments, it is estimated that 374 million new cases of syphilis, gonorrhea, chlamydia, and trichomoniasis occur worldwide every year. In the United States alone, over 12 million new cases of these four infections were reported in 2021, according to the Centers for Disease Control and Prevention (CDC).

This article will describe the causes and symptoms of four curable sexually transmitted infections, including how each is treated.

Vial and STD form
Rodolfo Parulan Jr. / Getty Images

Gender Definitions

For the purpose of this article, "females" refer to people with vaginas, and "males" refer to people with penises irrespective of the gender or genders they identify with.


Syphilis is an STI caused by corkscrew-shaped bacteria known as Treponema pallidum. The bacteria are passed from person to person through unprotected oral, anal, and vaginal sex.

Syphilis causes highly contagious, open sores known as chancres, primarily on the penis, anus, and vagina. In addition to being sexually transmitted, syphilis can be passed from a pregnant person to their unborn baby.

In 2021, the CDC estimated that 146,000 people were newly infected with syphilis in the United States.


Syphilis has been called the "Great Imitator" because its symptoms are often confused with other diseases. People with syphilis can sometimes go for years without symptoms. In fact, in the early stages, the painless sores may go unnoticed, particularly if they are hidden in the vagina or anus.

Syphilis progresses in four characteristic stages, and symptoms vary by the stage as follows:

  • Primary stage: Typically during this stage, a single round, painless chancre erupts on the genitals, vagina, or anus 10 to 90 days after infection. The chancre will last for three to six weeks and heals without treatment.
  • Secondary stage: Even as the chancre starts to heal, secondary symptoms can develop, such as a rash (including on the palms and feet) and flu-like symptoms like fatigue, fever, sore throat, and muscle aches. This stage can last two to six weeks.
  • Latent stage: The latent stage is the long period in which there are few if any symptoms. Latency can last for decades and, for some people, the infection may not progress beyond this stage.
  • Tertiary stage: This is the most advanced stage when syphilis can reap sudden, severe damage to the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints. Death can occur without aggressive antibiotic treatment.


In its early stages, syphilis is easily treated with a single dose of penicillin given by intramuscular injection (a shot into a large muscle). At later stages, different forms, doses, and durations of penicillin therapy may be needed to resolve the infection.

Other antibiotics may be used if a person has a penicillin allergy. Even so, the dangers of tertiary syphilis are so great that penicillin should still be used, albeit with penicillin desensitization therapy to reduce your sensitivity to the drug.


Gonorrhea is an STI caused by a bacteria known as Neisseria gonorrhoeae. Infection occurs through unprotected anal, vaginal, or oral sex. Ejaculation of semen is not required for infection to occur. Gonorrhea can also be passed to an unborn baby during pregnancy.

In 2021, the CDC estimated that 1.6 million people were newly infected with gonorrhea in the United States.


Many males with gonorrhea have no symptoms. If they do, they usually appear within a week of infection and cause:

  • Burning with urination
  • A white, green, or yellow discharge from the penis
  • Painful or swollen testicles

Females frequently have only minor symptoms or no symptoms at all. If they do, they include:

  • Pain or burning with urination
  • Vaginal discharge
  • Vaginal bleeding between periods

Both males and females can get rectal gonorrhea, causing symptoms like:

  • Rectal discharge
  • Anal itching or pain
  • Anal bleeding
  • Painful bowel movements

A gonorrhea infection in the throat may cause a sore throat or no symptoms at all.


There are several antibiotics that are successful in treating gonorrhea. However, gonorrhea strains that are resistant to antibiotics are becoming more and more common.

Today, a single dose of the antibiotic drug ceftriaxone is the preferred treatment for gonorrhea, which is given by intramuscular injection.

If gonorrhea is left untreated, it can cause other serious and possibly permanent complications like:


Chlamydia is the most frequently reported STI in the world, caused by a bacteria known as Chlamydia trachomatis. Because the symptoms of chlamydia are usually mild or absent, people who have chlamydia are unaware of the infection.

Chlamydia is spread from person to person during unprotected anal, vaginal, or oral sex. In addition, chlamydia can be passed to newborn babies during vaginal childbirth.

Chlamydia frequently co-occurs with gonorrhea, so most tests used to detect chlamydia also detect gonorrhea so that both can be treated together if needed.

In 2021, the CDC estimated that 4 million people were newly infected with chlamydia in the United States.


About 75% of females and 50% of males who have chlamydia have no symptoms. If symptoms appear, they usually do so one to three weeks after infection.

In females, symptoms of chlamydia include:

  • Vaginal discharge
  • Burning or pain during urination
  • Abdominal and/or low back pain
  • Nausea
  • Fever
  • Pain with intercourse
  • Vaginal bleeding between periods

Symptoms of chlamydia in males include:

  • Burning or pain during urination
  • Penile discharge
  • Burning and itching in the urethra (the tube through which urine exits the body)

If left untreated, chlamydia can cause permanent damage to the reproductive system and lead to infertility. As with gonorrhea, chlamydia can cause PID.


The treatment of chlamydia consists of either a single dose of the antibiotic azithromycin, a seven-day, twice-daily course of the antibiotic doxycycline, or a seven-day, once-daily course of the antibiotic levofloxacin.


Trichomoniasis is the most common STI in the United States. It affects both males and females, but symptoms are more common in females. The disease is caused by a one-celled parasite known as Trichomonas vaginalis.

Trichomoniasis is spread from person to person by way of unprotected sex, mainly vaginal intercourse.

In 2021, the CDC estimated that 6.9 million people were newly infected with trichomoniasis in the United States.


Many people with trichomoniasis have no symptoms. If symptoms occur, they usually appear within four weeks of exposure to the parasite.

Symptoms of trichomoniasis in females include:

  • Genital inflammation
  • Foul-smelling, yellow-green vaginal discharge
  • Pain with intercourse or urination
  • Vaginal irritation and itching
  • Abdominal pain

Symptoms of trichomoniasis in males :

  • Irritation and itching of the urethra
  • Penile discharge
  • Burning after urination
  • Buring after ejaculation ("cumming")

In pregnant people, having trichomoniasis increases the risk of preterm (premature) birth and low birth weight.


Females with trichomoniasis are easily treated with a single dose of an antibiotic called metronidazole, which can treat certain parasitic infections as well as bacterial ones.

In males, the infection will usually go away without treatment. However, because males are often unaware of their infection, they can reinfect their female partner again and again.

Therefore, treatment of both partners is recommended when one partner is diagnosed with trichomoniasis. This can better ensure the cycle of reinfection is stopped.

2 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. World Health Organization. Sexually transmitted infections (STIs).

  2. Centers for Disease Control and Prevention. Incidence, prevalence, and cost of sexually transmitted infections in the United States.

Additional Reading

By Mark Cichocki, RN
Mark Cichocki, RN, is an HIV/AIDS nurse educator at the University of Michigan Health System for more than 20 years.