A Guide to Sexually Transmitted Diseases (STDs)

Medically Reviewed By Elizabeth Thottacherry, MD
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Sexually transmitted diseases (STDs) are diseases and infections that are spread through sexual activity. Transmission typically occurs via vaginal, anal, and oral sex. This article will explain what STDs are. It will also discuss the symptoms and treatments of some of the most common STDs, as well as how to prevent them.

Sex and gender exist on a spectrum. This article uses the terms “female” and “male” to refer to sex that was assigned at birth. 

Learn more about the difference between sex and gender here.

What are STDs?

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The term STD refers to any one of the 35 or more infectious organisms that spread through sexual activity.

STDs are very common. According to the Centers for Disease Control and Prevention (CDC), there were around 2.4 million cases of chlamydia, gonorrhea, and syphilis in the United States in 2020. Using 2018 data, the CDC also estimates that 1 in 5 people had an STD of some kind.

Many people commonly refer to STDs as sexually transmitted infections (STIs). Both terms describe conditions that develop from organisms that spread through sexual activity.

Person-to-person transmission of STDs typically occurs through vaginal, anal, or oral sex. Many people who have an STD do not experience any symptoms. However, transmission to someone else is still possible.

Without treatment, some STDs can lead to serious complications like infertility.

This is why it is important to get regular testing for STDs and use safe sexual practices, like using a barrier method every time you have sex, to help prevent transmission.

Learn 8 surprising facts about STDs.

Gonorrhea

Gonorrhea is a very common STD, especially among those ages 15–24 years. You can develop gonorrhea in your throat, rectum, or genitals.

Anyone who is sexually active is at risk of developing gonorrhea. Regular testing, at least once a year, can help you prevent transmission to others. If you have multiple sexual partners, you are at a higher risk of developing gonorrhea or other STDs.

Symptoms

Oftentimes, people with gonorrhea do not experience any symptoms.

Females who do experience symptoms can often mistake them for a bladder or vaginal infection, as they tend to be mild. They may experience:

  • pain or burning while urinating
  • increased vaginal discharge
  • vaginal bleeding between periods
  • sore throat, in cases of pharyngeal gonorrhea

Males who experience symptoms may notice:

  • burning sensation when urinating
  • white, yellow, or green discharge from the penis
  • painful or swollen testicles, though this is less common
  • sore throat, in cases of pharyngeal gonorrhea

Rectal infections from gonorrhea may include symptoms like:

  • discharge
  • itching
  • soreness
  • bleeding
  • painful bowel movements

Since gonorrhea may not have any symptoms, it is important to get regular testing, especially if you think you may have had exposure to the infection. Untreated gonorrhea can lead to complications like pelvic inflammatory disease and infertility.

Treatment

Treatment for gonorrhea is a course of antibiotics. It is important to complete the full cycle of antibiotics that your doctor prescribes. Another treatment is a one-time intramuscular injection given in your doctor’s office.

Abstaining from sex during this period and for 7 days after your last dose is also important to prevent transmission to others. Any sexual partners should also have a test for gonorrhea and may require treatment as well.

If you have had gonorrhea before, you can still get it again if you have sex without a barrier method with someone who has it.

Chlamydia

Chlamydia is a common and treatable STD. It spreads through vaginal, anal, and oral sex. You can still develop chlamydia even if your partner does not ejaculate.

If you are sexually active, you are at risk of developing chlamydia. It is important to get regular testing, at least once a year, in order to help prevent transmission to others.

If you have multiple sexual partners, using a barrier method every time you have sex can also lower your risk of contracting the virus and prevent transmission to others.

Symptoms

Chlamydia commonly has no symptoms. However, it can still spread to others and it can cause damage to the female reproductive system.

If you do experience symptoms, they may not occur for several weeks after your exposure to chlamydia.

Symptoms in females may include:

Symptoms in males may include:

  • discharge from your penis
  • burning sensation when you urinate
  • painful and swollen testicles, though this is less common

Rectal symptoms of chlamydia may include:

  • rectal pain
  • bleeding
  • discharge

Treatment

Treatment for chlamydia typically consists of oral antibiotics. It is important that you take all the medication your doctor prescribes for you.

It is also important to abstain from sex for 7 days after your treatment, whether this is a single-dose treatment or a 7-day course.

Reinfection is common with chlamydia. Talk with any sexual partners about receiving testing or treatment for chlamydia.

Human papillomavirus (HPV)

HPV is the most common STD in the U.S. In 2018, the CDC reported 43 million cases of HPV, mostly among those in their late teens and early 20s.

As with other STDs, HPV spreads through vaginal, anal, or oral sex. Most commonly, however, transmission occurs through vaginal and anal sex.

Anyone who is sexually active can get HPV. You may not notice any symptoms for years after infection.

The HPV vaccine can help prevent you from contracting HPV and prevent transmission to others.

Symptoms

HPV does not generally have any symptoms. Most people with HPV do not know they have it. Even without symptoms, transmission to others is possible.

HPV can lead to other health complications, such as genital warts and cervical cancer.

Some females discover they have HPV during a routine Pap test screening. Other people do not know until they undergo testing for a different condition.

Treatment

There is no treatment for HPV itself. However, treatment is typically available for the conditions that can develop from HPV infection, particularly with early detection.

Speak with your doctor about your individual HPV results and available treatment options.

Syphilis

Syphilis is an STD that can cause serious health issues without treatment. Syphilis develops in stages that include:

  • primary
  • secondary
  • latent
  • tertiary

Syphilis spreads through contact with infected sores during vaginal, anal, and oral sex. Anyone who is sexually active can develop syphilis.

If you have multiple sexual partners, it is important to use a barrier method every time you have sex to prevent the spread of syphilis.

Symptoms

Each stage of syphilis has its own symptoms.

The symptoms for the primary stage include sores that develop in the following areas:

  • penis
  • vagina
  • anus
  • rectum
  • lips
  • mouth

The symptoms of the secondary stage include a rash that may occur on your palms or the bottoms of your feet. The rash may appear:

  • rough
  • red
  • reddish-brown

Other symptoms of this stage may include:

The latent stage is a period of time when you experience no visible symptoms. Most people with syphilis will not experience the tertiary stage. However, for those who do, it typically affects the:

You may not experience the tertiary stage for 10–30 years after you first develop syphilis.

Treatment

You can treat syphilis with antibiotics, such as an intramuscular injection of penicillin. It is important to get treatment as soon as possible as untreated syphilis can lead to serious health issues.

Trichomoniasis

Trichomoniasis (trich) is a common STD, especially among females.

The CDC estimates that there were 2 million cases of trich in the U.S. in 2018. However, only 30% of those with trich experienced any symptoms. Even with no symptoms, the infection can still spread to others.

Trich is spread through sex without a barrier method. It is due to a parasite that spreads during sex from penis to vagina, vagina to penis, or vagina to vagina.

Symptoms

The majority of people with trich do not experience any symptoms at all. When symptoms are present, they typically range from mild to severe.

Females who experience symptoms may notice:

  • itching, burning, redness, or swelling of the genitals
  • discomfort when urinating
  • clear, white, yellow, or green discharge with a fishy smell

Males may experience symptoms that include:

  • itching and irritation inside the penis
  • burning sensation after urinating or ejaculating
  • discharge

Treatment

Trich is very common and treatable. Typical treatment is a medication that your doctor can prescribe for you.

Reinfection with trich is also very common. About 1 in 5 people will develop trich again within 3 months. This is due to not using a barrier method when having sex.

Abstain from having sex until you and your partner have both completed treatment for trich.

What are other STDs?

There are many infections and diseases that spread through vaginal, anal, or oral sex.

Other STDs include:

Learn 4 discreet ways to get tested for STDs.

What are the risk factors for STDs?

If you are sexually active, you are at risk of developing an STD. There are certain factors that can increase your risk, however.

These risk factors include:

  • being younger than 25 years old
  • having multiple sexual partners
  • having sex with someone who has an STD
  • not using barrier methods when having sex, especially with new and multiple partners

How do you prevent STDs?

The only sure way to prevent an STD is not to have vaginal, anal, or oral sex. However, there are ways you can decrease your risk of developing an STD if you are sexually active.

Tips to help prevent STDs

  • Be in a monogamous sexual relationship with someone who does not have an STD.
  • Use a barrier method every time you have sex, especially with new and multiple partners.
  • Get regularly testing for STDs.
  • Get the HPV vaccine.
  • Take PrEP medication to help prevent HIV infection.

Summary

STDs are very common. If you are sexually active, you are at risk of developing an STD.

You can decrease your risk of developing an STD by using barrier methods when you have sex, getting regular testing, and making sure your partners have testing as well.

Most STDs are treatable. However, many do not typically have any symptoms. If you feel you may have had exposure to an STD or are experiencing symptoms like burning when urinating and unusual discharge, contact your doctor.

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Medical Reviewer: Elizabeth Thottacherry, MD
Last Review Date: 2022 Jun 30
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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