Women using her laptop while sitting on a couch researching sexually transmitted infections.

The complete glossary on sexually transmitted infections

by Gabrielle Kassel, Contributing writer

Ever wondered, “What’s the difference between an STI and STD”, “Is HIV the same as AIDS” or “What’s a finger condom”? Rather than taking the query to your search bar, keep reading.

What you should know about sexually transmitted infections (STIs)

Below, you’ll find definitions of all the terms in the sexually transmitted infection lexicon you could possibly need to know, broken down by categories.

First, what’s the difference between an STI and STD

STD: STD stands for sexually transmitted disease. Disease implies symptoms. So, sexually transmitted infections are only diseases when there are symptoms (for example: bumps, itching, or discharge) present.

STI: The now-preferred term in the sexual health space, STI stands for sexually transmitted infection. The switch from disease to infection took place to reduce stigma around these infections and to acknowledge the fact that the majority of these infections are asymptomatic.

All STIs are either curable or treatable

Curable: A curable STI is an STI that can be cleared up completely with the proper medication. Curable STIs include: gonorrhea, pubic lice, chlamydia, syphilis, and trichomoniasis.

Not only can curable STIs be cured, but they should be — leaving an STI untreated puts you at risk for things like pelvic inflammatory disease, infertility, and even death in the case of syphilis. That’s why it’s so important to get tested after every new sexual partner. And, if positive to talk to your provider and come up with a cure plan.

Treated: STIs that cannot be cured can be treated. Meaning, the symptoms associated with that STI can be managed with the help of lifestyle changes, and/or medication. Treatable STIs include: HIV, HSV, and HPV.

An example of treating — but not curing — an STI, might include taking valacyclovir or acyclovir, an oral antiviral medication that can either be taken daily (suppressive therapy) or at the first sign of outbreak (intermittent therapy). What makes most sense for you will depend on factors like cost and frequency of outbreaks. Because research has suggested a link between the number of outbreaks in HSV-positive people and stress, managing stress levels is another example.

Types of sexually transmitted infections, explained

AIDS: Also known as HIV Stage 3, AIDS (acquired immunodeficiency syndrome) develops when the HIV virus severely damages a person’s immune system.

In the U.S., most people who are HIV-positive never develop AIDS because they’re on medications that prevent the infection from progressing to AIDS. Due to lack of access, globally AIDS is much more common, but numbers are dropping.

Chlamydia: Caused by a bacteria, chlamydia is a curable STI that infects 4 million Americans each year, the majority of who are under 25 and women.

When symptoms appear, they usually include abnormal discharge, pain or frequent urination or bleeding after sex and/or between periods — but chlamydia is usually asymtomatic. The infections and accompanying symptoms can be cured up with proper antibiotics.

Crabs: Also known as pubic lice, crabs are itty-bitty parasites that feast on blood that are found on pubic hair (and other course body hair). Typically, crabs are transmitted during intimate contact between the pubes of a person with crabs and the pubes of someone else.

The most common symptoms of crabs is genital itching, but you may also be able to see the white-colored, micro-crabs crawling around between your legs. Crabs can be cured through special over-the-counter creams or shampoos. Important: Because crabs lay eggs (known as nits), after treatment then nits need to be removed with fingernails or comb.

Genital Warts: Genital warts are fleshy skin tags caused by a few strains of HPV (see “HPV” below). These contagious warts may be accompanied by itchiness, but can be treated with topical medication or by being removed by a healthcare provider.

Gonorrhea: Also caused by bacteria and also curable, gonorrhea is an infection responsible for half a million new STI cases in the United States each year.

Much like chlamydia, gonorrhea is hard to recognize due to its often asymptomatic nature. But, when symptoms do pop up they usually include: genital itching, bleeding, abdominal pain, abnormal genital discharge, and soreness and sore throat. To diagnose and get the medicine that will eliminate the infection from your body, go to your local walk-in clinic or healthcare provider.


Short for human immunodeficiency virus, HIV is a viral infection that attacks the body’s immune system making it hard for the body to fight any other infection, including common, everyday viruses. Wrongly known as a gay man’s virus, HIV is an STI that can affect all people.

Hepatitis A

A contagious viral liver infection caused by the Hepatitis A virus, Hepatitis A typically clears up on its own within a few months. Hepatitis A is not just sexually transmitted — it can also be transmitted through contaminated foods.

Hepatitis B

Hepatitis B is a contagious viral liver infection caused by the Hepatitis B virus that can be transmitted via exposure to the bodily fluids of an infection person. The difference between this form of Hepatitis, however, and the others is that Hepatitis B can be prevented with a vaccine.

Hepatitis C

Hepatitis C is a viral liver infection that can be spread through blood, breast milk, or pregnancy. Untreated, the infection can become life-threatening. But diagnosed and with proper treatment, the infection can be cured 90 percent of the time.


With more than 100 different strains, human papillomavirus (HPV) is the most common sexually transmitted infection in the world. Symptoms, long-term health risks, and treatment vary strain-by-strain.


Better-known by its full name, herpes, HSV is a lifelong viral infection caused by the herpes simplex virus that can be managed with proper care.

There are two distinct strains of the herpes infection: HSV-1 and HSV-2. Often, these are incorrectly re-named as “oral herpes” or “genital herpes” but both strains can affect areas like the vagina, anus, penis, or mouth.

Molloscum Contagiosum

Molloscum contagiosum is a viral infection spread through skin-to-skin contact, that causes benign bumps along infected areas. Sometimes the bumps will fade away on their own, other times they are removed through cryotherapy, laser therapy, or topical therapy with the help of  a healthcare professional.


Often called “trich”, trichomoniasis is a sexually transmitted infection caused by a parasite that can be cured with a dose of antibiotics. Symptoms are trichomoniasis are rare — especially in people with penises. But when symptoms do appear, they often include discharge, genital itching, and pain while urinating.


Syphilis is a progressive bacterial infection spread through sexual contact. The symptoms of the infection vary based on how long it’s been in your system, and range from a skin sore to fatigue and fever to liver dysfunction. If caught early enough it can be cured with a single shot of penicillin, but left untreated for too long the infection can spread to the brain and other organs, becoming life threatening.

Barrier methods and birth control

Here’s some information on protection options people can apply to help stay safe during sex.


Barrier is the general terms for a physical barrier that is designed to prevent direct skin-to-skin contact or fluid exchange during a sex act. Most common is the external condom. But there is also the internal condom, dental dam, glove, and finger condom.

Occasionally, certain birth control methods which do not prevent skin-to-skin contact or fluid exchange, but are highly effective at preventing a sperm from meeting an egg during vaginal intercourse — the sponge, cervical cap, diaphragm, and spermicide — are also qualified as a barrier.

Birth Control

Also known as contraception, birth control is designed to help prevent unwanted pregnancy. There’s a variety of different types of birth control options, which all function differently as well as feature  slightly different levels of effectiveness.


There are a few different types of condoms: finger condoms, internal condoms, and external condoms. But typically when people say “condom” they’re referring to the external variety. (See: “external condom” below).

Dental Dams

Dental dams are sheaths of latex designed to prevent direct contact between a mouth and an anus or vagina, and therefore reduce the risk of STI transmission.

External Condoms

External condoms are tight latex, polyurethane or polyisoprene tubes designed to go over a penis during vaginal, anal, or oral intercourse to protect against STI transmission and/or pregnancy. They are also often used on dildos and other pleasure products to increase ease during clean-up as well as to allow for sex-toy sharing between non-fluid-bonded partners.

Finger Cots

Sometimes called finger condoms, finger cots are micro-sized external condom designed to fit over a single digit. While most commonly worn by doctors sporting paper cuts, they can also be warn during vaginal or anal fingering to keep from or reduce the risk of STI transmission.

Fluid Bonded

Refers to sexual partners who have intentionally decided to forgo barriers and exchange bodily fluids during sex. Prior to becoming fluid-bonded, sexual partners typically discuss current STI status, potential risks, pregnancy prevention (if applicable), as well as relationship rules moving forward.

Internal Condoms

Formerly known as female condoms, internals condoms are soft, long tubes that are designed to line the vaginal or anal canal in order to prevent fluid exchange or skin-to-skin contact during vaginal or anal sex. Bonus: They are typically made out of nitrile as opposed to latex, making them a great alternative for those with latex allergies.


Post-exposure prophylaxis is a series of pills someone who was (or may have been!) exposed to HIV can begin taking up to 72 hours after exposure to prevent transmission of the virus.


Pre-exposure prophylaxis, as the prefix suggests, is a daily oral medication that can be taken by an HIV-negative person at risk of coming into contact with the virus, in order to greatly reduce the risk of the virus being transmitted.

Reviewed by the Ovia Health Clinical Team


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