STIs vs STDs: What's the Difference?

| Patient Education

STIs (sexually transmitted infections) and STDs (sexually transmitted diseases) are terms that are often used interchangeably to describe any medical condition that is transmitted through sexual activity. Understanding the difference between STIs and STDs can help you take a proactive approach to sexual health by staying informed.

Disease vs infection

The key difference between an STD and STI lies in how infections and diseases are defined. Infection occurs when viruses or bacteria enter the body and begin to multiply. When the body is fighting an infection, your immune system will deploy white blood cells and antibodies to eliminate the threat. Disease occurs when the cells in your body are damaged, which can often be the result of infection but can also be caused by injury, hereditary factors, and other environmental factors.

What’s the difference between an STD and STI?

An STI becomes an STD when symptoms appear; all STDs begin as STIs. Some STIs, like HPV, will clear without presenting any health problems and without medical intervention. In this case, HPV is an STI. However, if the body doesn’t eradicate the HPV virus it can cause warts or certain cancers, which is then defined as an STD.

While the difference between an STI and STD can seem arbitrary, it’s important to acknowledge that sexually transmitted infections can be present without any symptoms.

How are STIs spread?

Any sexual activity, including oral, anal, vaginal, and genital touching, can put you at risk for venereal infections. Some viruses can be transmitted through skin-to-skin contact while others require an exchange of bodily fluids like semen, vaginal secretions, or blood.

What are the symptoms of STDs?

Each STI could present different STD symptoms and could take days, weeks, or even years to appear. But there are some common signs to look for:

  • Bumps, sores, or rashes in or near the genitals
  • Genital discharge
  • Rectal bleeding
  • Pain during intercourse
  • Painful or swollen testicles
  • Burning or painful urination

Should I get tested?

The Centers for Disease Control and Prevention (CDC) recommends yearly screenings for sexually active adults. You may be at an increased risk for STIs and STDs if you have sex without a barrier (like a condom), have multiple sexual partners, or share injection equipment (like needles).

Unless you have reason to believe you’ve been exposed to an STI or experienced STD symptoms, a yearly screening should suffice for most. Many STIs like HPV and syphilis have long incubation periods and will not show up on a test after a recent infection.

Globally, the World Health Organization (WHO) estimates that more than one million people get an STI every day. STIs that are left untreated can develop into STDs with serious health implications including cancer, liver disease, and AIDS. While in practice STIs and STDs can be used interchangeably, a better understanding of sexually transmitted diseases can help to limit infection and development of disease.

If you have any questions or concerns about sexual health, we’re here to help. Reach out to your primary healthcare provider to learn more about STIs, STDs, and testing.