What Are Sexually Transmitted Diseases?

In This Article

Sexually transmitted diseases, or STDs, are diseases that primarily spread through sexual contact. There are several, most of which are bacterial or viral, and examples include herpes, chlamydia, gonorrhea, HIV, and HPV. Transmission may involve body fluids (blood, saliva, semen, vaginal secretions) or direct skin-to-skin contact. It's also possible for a mother to pass some STDs to her child in utero, during childbirth, or through breastfeeding.

Consistent use of condoms and other barriers can help prevent STDs, but they are not a guarantee or equally as effective for all infections. While abstinence is the only way to prevent STDs altogether, knowing the risk factors for transmission can help you protect yourself if you are sexually active.


According to the U.S. Centers for Disease Control and Prevention (CDC), more than 2 million people were treated for STDs in 2017—and rates of several STDs are on the rise.

Between 2013 and 2017, cases of syphilis increased by 76%, gonorrhea by 67%, and chlamydia by 22%. New cases of HIV, however, declined between 2010 and 2016, with 38,700 new cases reported in 2016.

In considering this, however, it's important to note that these are diagnosed cases. Given the way symptoms can present, more people are likely to be infected than these numbers reflect.

risk factors of stds
Verywell / Theresa Chiechi​

Sexually Transmitted Disease Symptoms

Genital itching, burning, or pain are common symptoms of an STD, although some people do not experience any symptoms.

Signs and symptoms, should they occur, may differ depending on the STD and can include:

  • Genital itching, swelling, or redness
  • Bumps, sores, warts, or rash near the mouth, anus, penis, or vagina
  • Unusual discharge from penis or vagina, which may or may not have an unusual order
  • Vaginal bleeding at times other than a monthly period
  • Painful urination
  • Painful sex
  • Aches, pains, fever, and chills
  • Jaundice
  • Weight loss, loose stools, and night sweats

Many STDs have no symptoms and the vast majority of people with an STD are asymptomatic, though they are still able to pass the infection to a partner.


Sexually transmitted diseases are mainly caused by intimate contact with an infected partner. This includes, but is not limited to, penetration, as skin-to-skin contact alone can transmit some infections.

STDs can also be passed from mother to baby during pregnancy. Some STDs, like syphilis and HIV, can be transmitted in utero while others, like herpes, are passed during delivery.

Anal intercourse is generally considered the riskiest form of sexual contact. That's followed by vaginal intercourse and oral sex; a growing number of genital herpes cases are caused by unprotected oral sex. Fingering and fisting also pose some risks, as does the use of sex toys.

Having safe sex isn't a guarantee you won't get or give an STD, but consistently using appropriate barriers greatly reduces the odds.

There's no simple way to determine a person's level of risk by looking at them. Risk is based far more on geography, history, and behavior than age, race, sexual orientation, or gender. That's one of the many reasons it's a good idea to sit down and talk with your partner (and get tested) before having sex.

If you're in a mutually monogamous relationship in which both you and your partner have tested negative for STDs, your risk is likely quite low. Some level of risk still persists, however, as there are some STDs that doctors can't, or don't, test for.


If you think you may have an STD because you have symptoms or had sex with an infected or high-risk partner, talk to your doctor. They will perform a physical examination and run tests for common STDs.

The only way to know if you have an STD is to get tested. It's impossible to diagnose most STDs by looking at yourself, even if you do have visible signs of an infection. Regular STD screening is so important for anyone having sex outside of a mutually monogamous relationship.

Tests your doctor will perform may include a urine sample, cheek swab, blood work, or fluid samples such as discharge from sores. In addition, your doctor may take cell cultures from the penis, vagina, urethra, cervix, anus, or throat.

You may need to wait a period before an STD test will show accurate results or be retested at a later date.


If you have an STD, it is important to get treated and prevent infecting others. Treatment varies based on the type of infection.

Viral infections, such as herpes, HPV, and HIV, are usually treated with oral antiviral or antiretroviral medications. However, most viral STDs cannot be cured and these medications are used to treat the symptoms, prevent recurring outbreaks, and halt the progression of the disease.

Bacterial infections, such as syphilischlamydia, and gonorrhea, are treated with antibiotics. Unlike viral STDs, they are generally curable with the right treatment.

Other types of STDs can be treated topically or orally. For examples, scabies can be treated either using drugs you take by mouth or through the use of topical agents. Pubic lice are treated topically.


STDs are largely preventable by consistently and correctly practicing safe sex. Your can also reduce your risk of STDs by being in a long-term monogamous relationship where both you and your partner have been tested for STDs and are maintaining honest communication with one another.

Diseases that are transmitted only by body fluids, such as HIV and chlamydia, can be prevented with consistent use of barriers during sex. It's much harder to completely prevent diseases that spread from skin-to-skin, like herpes. (Barriers help, but it simply isn't practical to cover all potentially infectious skin.)

A Word From Verywell

People are often terrified of an STD diagnosis and may avoid doctors and testing. The truth is, however, that STDs aren't the end of the world. They are incredibly common and something that you can live with.

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Article Sources
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  2. Morris SR. Overview of Sexually Transmitted Diseases (STDs). Merck Manual Consumer Version. 2018.

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  4. Centers for Disease Control and Prevention. STD Risk and Oral Sex - CDC Fact Sheet. Updated December 1, 2016.

  5. Workowski KA, Bolan GA. Sexually transmitted diseases treatment guidelines, 2015. MMWR Recomm Rep. 2015;64(RR-03):1-137.

  6. Wagenlehner FM, Brockmeyer NH, Discher T, Friese K, Wichelhaus TA. The Presentation, Diagnosis, and Treatment of Sexually Transmitted InfectionsDtsch Arztebl Int. 2016;113(1-02):11–22. doi:10.3238/arztebl.2016.0011

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