Everything You Need to Know About Sexually Transmitted Diseases

STIs vs. STDs
Often confused, sexually transmitted infections (STIs) and sexually transmitted diseases (STDs) aren’t actually the same thing.

An infection —which is when bacteria, viruses, or parasites attack the body —comes before a disease.

And while an infection may result in zero symptoms, a disease usually always comes with clear signs.

Now you know the difference between the two, here’s the lowdown on the types of STDs that currently exist, how to treat them, and, most importantly, how to prevent them.

STD symptoms
If an STD starts with a symptomatic STI, you might first experience:

  • pain or discomfort during sexual activity or urination
  • sores, bumps, or rashes on or around the vagina, penis, testicles, anus, buttocks, thighs, or mouth
  • unusual discharge or bleeding from the penis or vagina
  • painful or swollen testicles
  • itchiness in or around the vagina
  • unexpected periods or bleeding after sexual activity

But remember that not all STIs have symptoms.
If an STI progresses to an STD, symptoms can vary. Some of them may be similar to the above, such as pain during sexual activity, pain during urination, and irregular or painful periods.

But other symptoms can be quite different and depend on the STD. They can include:

  • fever
  • recurring pain
  • fatigue
  • memory loss
  • changes to vision or hearing
  • nausea
  • weight loss
  • lumps and swelling

Underlying STD causes
All STDs are caused by an STI.
These infections are usually transmitted through sexual contact Trusted Source, including through bodily fluids or skin contact via vaginal, oral, and anal sex.

Some of them never become a disease, especially if they’re treated, and they can even go away on their own.

But if the pathogens that caused the infection end up damaging cells in the body and disrupting its functions, an STI will progress to an STD.

Types of STDs

While the list of STIs is pretty lengthy, there are fewer STDs.

They range from pelvic inflammatory disease (PID), caused by STIs like chlamydia and gonorrhea, to some forms of cancer, caused by human papillomavirus (HPV).

Below are the main STDs to be aware of.

Pelvic inflammatory disease

Gonorrhea, chlamydia, and trichomoniasis are common STIs that can lead to PID Trusted Source if left untreated.

But not all cases of PID are caused by an STI, as other bacterial infections can play a role.

Around 2.5 million women Trusted Source in the United States have a reported lifetime history of being diagnosed with PID, according to the Centers for Disease Control and Prevention (CDC).

Although this infection of the female reproductive organs is classified as a disease, some people have no symptoms.

Those who do have symptoms may experience:

  • pelvic or lower abdominal pain
  • pain during penetrative vaginal sex or when urinating
  • irregular, heavy, or painful vaginal bleeding
  • unusual vaginal discharge
  • nausea
  • high temperature
  • Antibiotics can successfully treat PID if it’s diagnosed early enough. However, they won’t treat any scarring on the fallopian tubes that may have occurred.

This scarring can make an ectopic pregnancy more likely and has also been linked to infertility, with around 1 in 10 people with PID becoming infertile as a result.

Tertiary syphilis

The early stages of syphilis —a relatively uncommon infection — are considered an STI.

The infection first appears as one or more small round sores on the genitals, anus, or mouth. If left untreated, syphilis will move to the latent phase, which has no symptoms Trusted Source.

However, around a quarter of people will go on to develop tertiary syphilis from here —a process that can take between 10 and 30 years after the initial infection.

This disease can have serious consequences for several organ systems in the body, leading to:

  • loss of vision
  • loss of hearing
  • memory loss
  • mental health conditions
  • infections of the brain or spinal cord
  • heart disease

The earlier syphilis is diagnosed and treated, the less damage it does.

While penicillin injections are typically used to treat tertiary syphilis and remove the bacteria from the body, they can’t reverse any damage that’s already occurred.

Of course, if the disease causes problems with major organs, like the heart, other medications and procedures may be required.


HIV can damage the immune system and increase the risk of contracting other viruses or bacteria and developing certain cancers.

With today’s treatments, many people with HIV live long, healthy lives.

But if left untreated, the virus can lead to AIDS, where the body becomes vulnerable to serious infections and illnesses.

People with AIDS may experience:

  • rapid weight loss
  • extreme fatigue
  • sores
  • infections
  • neurologic disorders
  • cancers

No cure is available for AIDS. And due to the variety of diseases that can be contracted as a result of a severely weakened immune system, life expectancy without treatment is around 3 years Trusted Source.

The bottom line

Many STDs are treatable, but not all of them are curable. Some can be life threatening, while others have less serious effects.

They are, however, all caused by an STI. So the best way to prevent them is to get regularly screened and practice safer sex.

And if you test positive for any STI, seek treatment as soon as possible.


About HIV. (2021).


Acute pelvic inflammatory disease. (2016).


Brown DL, et al. (2003). Diagnosis and management of syphilis.


Diseases and related conditions. (2021).


Genç M, et al. (2000).


Genital warts. (n.d.).


Genital warts symptoms & treatment. (2021).


HIV and AIDS. (2021).


HPV and cancer. (2021).


How do I get treated for genital warts? (n.d.).


Pelvic inflammatory disease. (2018).


Pelvic inflammatory disease (PID). (2019).


Pelvic inflammatory disease (PID) – CDC fact sheet. (2020).


Pregnancy and cancer. (2019).


Signs and symptoms of cancer. (2020).


STI vs. STD: key differences and resources for college students. (n.d.).


Symptoms of HIV. (2020).


Syphilis. (2019).


Syphilis – CDC fact sheet. (2017).


Syphilis: Frequently asked questions. (n.d.).



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