All About STDs/STIs

A sexually transmitted infection (STI) is a virus, bacteria, fungus, or parasite people can get through sexual contact. A sexually transmitted disease (STD) develops because of an STI, and the term implies that the infection has led to some symptom of disease. STIs pass from one person to another through vaginal, oral, and anal sex. They also can spread through intimate physical contact like heavy petting, though this is not very common. 

There are dozens of STIs.

Some STIs are spread mainly by sexual contact, such as:

Bacterial Vaginosis (BV) 

Bacterial vaginosis (BV) is a condition that happens when there is too much of certain bacteria in the vagina, causing an imbalance. BV is the most common vaginal condition in people with vaginas ages 15-44. Douching, not using condoms, and having new or multiple sex partners can upset the normal balance of vaginal bacteria, increasing your risk for getting BV.

Chlamydia 

Chlamydia is a common STI that can cause infection among sexually active people. It can cause permanent damage to a person’s uterus and fallopian tubes. This can make it difficult or impossible to get pregnant later. Chlamydia can also cause a potentially fatal ectopic pregnancy (pregnancy that occurs outside the womb). Even when chlamydia has no symptoms, it can damage the reproductive system. 

People with vaginas with symptoms may notice: 
  • An abnormal vaginal discharge 
  • A burning sensation when peeing 
  • Symptoms in their partners 
People with penises with symptoms may notice: 
  • A discharge from their penis 
  • A burning sensation when peeing 
  • Pain and swelling in one or both testicles (although this is less common) 
  • Symptoms from rectal infections 
  • Symptoms in their partners 
All people can also get chlamydia in their rectum.  While these infections often cause no symptoms, they can cause: 
  • Rectal pain 
  • Discharge 
  • Bleeding 

Herpes

Herpes sores usually appear as one or more blisters on or around the genitals, rectum or mouth. This is known as having an “outbreak.” The blisters break and leave painful sores that may take a week or more to heal. Flu-like symptoms (e.g., fever, body aches, or swollen glands) also may occur during the first outbreak. Mild symptoms may go unnoticed or be mistaken for other skin conditions like a pimple or ingrown hair. Genital herpes is common in the United States. In 2018, the Centers for Disease Control estimates there were 572,000 new genital herpes infections in the U.S. among people aged 14 to 49.

You can get genital herpes by having vaginal, anal, or oral sex with someone who has the infection.

You can get herpes if you have contact with: 
  • A herpes sore 
  • Saliva from a partner with an oral herpes infection 
  • Genital fluids from a partner with a genital herpes infection
  • Skin in the oral area of a partner with oral herpes  
  • You also can get genital herpes from a sex partner who does not have a visible sore or is unaware of their infection. It is also possible to get genital herpes if you receive oral sex from a partner with oral herpes. 
  • Skin in the genital area of a partner with genital herpes 

You cannot get herpes from toilet seats, bedding, or swimming pools. You also will not get it from touching objects, such as silverware, soap, or towels. 

Gonorrhea 

  • Gonorrhea is an STI that can cause infection in the genitals, rectum, and throat. It is very common, especially among young people ages 15-24 years.
  • Most people with vaginas with gonorrhea do not have any symptoms. Often, symptoms are mild and can be mistaken for a bladder or vaginal infection.
Symptoms can include:
  • Painful or burning sensation when peeing 
  • Increased vaginal discharge 
  • Vaginal bleeding between periods 
People with penises who do have symptoms may have:
  • A white, yellow, or green discharge from the penis 
  • Painful or swollen testicles (although this is less common) 

Rectal infections may cause:

  • Discharge 
  • Anal itching 
  • Soreness 
  • Bleeding 
  • Painful bowel movements 

You can get gonorrhea by having vaginal, anal, or oral sex without a condom with someone who has the infection. A pregnant person with gonorrhea can give the infection to their baby during childbirth. 

Human Papillomavirus (HPV) 

HPV, or human papillomavirus, is a very common virus that can cause cancers later in life. Nearly everyone will get HPV at some point in their lives. More than 42 million Americans are infected with types of HPV that are known to cause disease. About 13 million Americans, including teens, become infected each year.

Most HPV infections (9 out of 10) go away by themselves within 2 years. But sometimes, HPV infections will last longer and can cause some cancers.

HPV is spread through intimate skin-to-skin contact. You can get HPV by having vaginal, anal, or oral sex with someone who has the virus, even if they don’t have signs or symptoms.

HPV infections can cause cancers of the: 
  • Cervix, vagina, and vulva
  • Penis 
  • Anus
  • Back of the throat (called oropharyngeal cancer), including the base of the tongue and tonsils 

Everyone through age 26 years should get HPV vaccine if they were not fully vaccinated already. 

Syphilis 

Syphilis is an STI that can cause serious health problems without treatment. Infection develops in stages (primary, secondary, latent, and tertiary).

Each stage can have different signs and symptoms. 

PRIMARY stage 

During the first (primary) stage of syphilis, you may notice a single sore or multiple sores. The sore is the location where syphilis entered your body.

These sores usually occur in, on, or around the

  • Penis
  • Vagina
  • Anus
  • Rectum
  • Lips or in the mouth
  • Sores are usually (but not always) firm, round, and painless. Because the sore is painless, you may not notice it. The sore usually lasts 3 to 6 weeks and heals regardless of whether you receive treatment. Even after the sore goes away, you must still receive treatment. This will stop your infection from moving to the secondary stage.

Secondary stage 

During the secondary stage, you may have skin rashes and/or sores in your mouth, vagina, or anus. This stage usually starts with a rash on one or more areas of your body. The rash can show up when your primary sore is healing or several weeks after the sore has healed. The rash can be on the palms of your hands and/or the bottoms of your feet and look rough, and reddish-brown. The rash usually won’t itch, and it is sometimes so faint that you won’t notice it.

Other symptoms can include,

  • Fever
  • Swollen lymph glands
  • Sore throat
  • Patchy hair loss
  • Headaches
  • Weight loss
  • Muscle aches
  • fatigue (feeling very tired)

The symptoms from this stage will go away whether you receive treatment. Without the right treatment, your infection will move to the latent and possibly tertiary stages of syphilis.

Latent STAGE 

The latent stage of syphilis is a period when there are no visible signs or symptoms. Without treatment, you can continue to have syphilis in your body for years.

Tertiary STAGE

Most people with untreated syphilis do not develop tertiary syphilis. However, when it does happen, it can affect many different organ systems. These include the heart and blood vessels, and the brain and nervous system. Tertiary syphilis is very serious and would occur 10–30 years after your infection began. In tertiary syphilis, the disease damages your internal organs and can result in death. A health care provider can usually diagnose tertiary syphilis with the help of multiple tests. 

Neurosyphilis, ocular syphilis, and otosyphilis 

Without treatment, syphilis can spread to the brain and nervous system (neurosyphilis), the eye (ocular syphilis), or the ear (otosyphilis). This can happen during any of the stages described above.

Signs and symptoms of neurosyphilis can include

  • Severe headache
  • Muscle weakness and/or trouble with muscle movements
  • Changes to your mental state (trouble focusing, confusion, personality change) and/or dementia (problems with memory, thinking, and/or decision making).

Signs and symptoms of ocular syphilis can include

  • Eye pain and/or redness
  • Changes in your vision or even blindness
  • Signs and symptoms of otosyphilis may include
  • Hearing loss
  • Ringing, buzzing, roaring, or hissing in the ears (“tinnitus”)
  • Dizziness or vertigo (feeling like you or your surroundings are moving or spinning)

Mycoplasma genitalium (Mgen) 

Mycoplasma genitalium can infect the cervix (opening to the uterus), inside the penis (the urethra), or the rectum. People with Mgen often have no symptoms. 

MGEN symptoms include:

  • Vaginal discharge
  • A burning sensation when peeing
  • Discharge from the penis
  • You can get Mgen by having vaginal or anal sex without a condom with someone who has the infection. Researchers are still determining whether sex partners can spread Mgen through oral sex.
  • A person with Mgen can pass the infection to someone even when they have no signs or symptoms.

Pelvic Inflammatory Disease (PID) 

Pelvic inflammatory disease (PID) is an infection of the reproductive organs of people with vaginas, uterus, fallopian tubes, and/or ovaries. It is a complication often caused by some STIs, like chlamydia and gonorrhea. Other infections that are not sexually transmitted can also cause PID. 

You are more likely to get PID if you, 

  • Have an STI and do not get treated
  • Have more than one sex partner
  • Have a sex partner who has sex partners other than you
  • Have had PID before
  • Are sexually active and are age 25 or younger
  • Douche
  • Use an intrauterine device (IUD) for birth control. However, the small increased risk is mostly limited to the first three weeks after the IUD is placed inside the uterus by a doctor

There are no tests for PID. A diagnosis is usually based on a combination of your medical history, physical exam, and other test results. You may not realize you have PID because your symptoms may be mild, or you may not experience any symptoms.

However, if you do have symptoms, you may notice,

  • Pain in your lower abdomen 
  • Fever 
  • An unusual discharge with a bad odor from your vagina 
  • Pain and/or bleeding when you have sex 
  • Burning sensation when you urinate 
  • Bleeding between periods 

Trichomoniasis

Trichomoniasis (or “trich”) is a very common STI caused by infection with trichomonas vaginalis (a protozoan parasite). Although symptoms vary, most people who have trich cannot tell they have it.

About 70% of people with the infection do not have any signs or symptoms. When trich does cause symptoms, they can range from mild irritation to severe inflammation. Some people get symptoms within 5 to 28 days after getting the infection. Others do not develop symptoms until much later. Symptoms can come and go.

People with penises with trich may notice:

  • Itching or irritation inside the penis
  • Burning after peeing or ejaculating
  • Discharge from the penis

People with vaginas with trich may notice:

  • Itching, burning, redness or soreness of the genitals
  • Discomfort when peeing
  • A clear, white, yellowish, or greenish vaginal discharge (i.e., thin discharge or increased volume) with a fishy smell

Having trich can make sex feel unpleasant. Without treatment, the infection can last for months or even years.

Sexually active people can get trich by having sex without a condom with a partner who has trich.

For people with vaginas, the infection is most commonly found in the lower genital tract (vulva, vagina, cervix, or urethra). For people with penises, the infection is most commonly found inside the penis (urethra). During sex, the parasite usually spreads from a penis to a vagina, or from a vagina to a penis. It can also spread from one vagina to another vagina.

It is not common for the parasite to infect other body parts, like the hands, mouth, or anus. It is unclear why some people with the infection get symptoms while others do not.

References: 

All information on this page was derived from the Center for Disease control, and is the most comprehensive, up-to date, and evidence-based information.  
CDC (2024). Sexually Transmitted Infections (STIs). [online] Sexually Transmitted Infections (STIs). Available at: https://www.cdc.gov/sti/index.html.