Diagnosing and treating a sexually transmitted infection (STI) early is important. This limits the problems it can cause and helps prevent its spread to others. An STI is also known as a sexually transmitted disease (STD). Any sexual contact with the penis, vagina, anus, or mouth can spread a sexually transmitted infection (STI). STIs may not cause any symptoms but still get transmitted. If you think you may be at risk for an STI, get tested and treated right away. Ask your partner to get tested, too. Then don't have sex until you've finished treatment and your healthcare provider says it's OK.

Be alert to any changes in your body and your partner's body. Symptoms of an STI may appear in or near the vagina, penis, rectum, mouth, or throat. They may include:

• Abnormal discharge
• Lumps, bumps, or rashes
• Sores that may be painful, itchy, or painless
• Burning feeling or pain when you pee
• Pain in the pelvis, belly (abdomen), or rectum
• Bleeding or abnormal discharge from the rectum
• Pain during sex
• Painful periods
• Testicular pain

Your healthcare provider will take a health history and examine you. You'll be asked about your sex habits, such as sexual partners, condom use, and types of sex (vaginal, anal, oral) you have. You may also be asked about other risky behaviors, like drug use or past STIs. Give honest answers. Your provider will then check your body for signs of STIs. You may also need 1 or more of these tests:

• Swabs may be taken from the vagina, penis, mouth, or rectum. Sometimes you can collect the swab yourself. If you would be more comfortable doing that, ask your provider. The samples are then tested for STIs like chlamydia, gonorrhea, and trichomonas.
• Fluid may be swabbed from open sores.
• Urine samples may be taken. They're checked for bacteria or parasites that cause STIs, such as chlamydia, gonorrhea, and trichomonas.
• Blood samples may be taken. They're checked for viruses or bacteria that cause STIs, such as such as HIV, hepatitis, and syphilis.
• For women, cells from the cervix are checked for signs of cancer and the genital wart virus (HPV or human papillomavirus infection). This is called a Pap test. It is often now done along with HPV testing. If cell changes are found, or a high-risk type of HPV is found, a magnifying scope may be used to take a closer look (colposcopy).
• A Pap test may be done on the anus. This is to check for HPV-linked cancer or precancer changes. The provider gently swabs cells from the lining of the anus. This sample is then sent to a lab to be checked under a microscope. If there are any abnormal signs, you may need more testing.

Treatment depends on the type of STI you have. Common treatments include antibiotics. These may be pills, liquids, or shots (injections). Creams and gels can be put on sores or warts caused by certain STIs. Follow the tips below:

• Get new treatment for each new STI.
• Don't use old medicine, even for the same STI. Use medicines as directed.
• Don't share medicine unless instructed to do so by your healthcare provider or clinic.
• Take treatment for as long as your provider advises. If any side effects appear, contact your provider. Ask them what to do about it.
• Prevent future STIs by having safe sex practices.
• Don't have sex until you and your partner have completed treatment.

If you have an STI, it's your duty to tell all your recent sex partners so they can be tested and treated. This is one important way to prevent the disease from being spread. Telling a partner that you have an STI can be hard. You may be embarrassed, angry, or afraid. It's often unclear who had the STI first. So try not to place blame. Your healthcare provider may have some advice on how to start. If you do not feel comfortable telling your sex partner(s) about an STI, there are ways to inform your sex partner(s) anonymously. Ask your healthcare provider how to do this.

Even after you've been treated, you can still be infected again. This is a common problem. It can happen if a partner passes the STI back to you. To prevent this, any partners you have must be tested. They may also need treatment. After treatment, go to any scheduled follow-up visits. Then prevent future problems by practicing safer sex. Limit your number of partners. And always use a latex condom.

Remember that HIV is also an STI. If you have one type of STI, you can get others, including HIV. Ask your healthcare provider if you should take medicine to prevent getting HIV. This can be taken before the risk of exposure (PrEP or pre-exposure prophylaxis). Or it can be taken within 72 hours after unsafe sex (PEP or post-exposure prophylaxis).