Many STIs don’t cause any symptoms, so you may not know you have them. Some STDs are curable with antibiotics, and others (like HIV infection and herpes) persist and can cause serious problems if not treated early.

Men with gonorrhea might experience itching inside the penis or pain during urination and ejaculation. Women with trichomoniasis may notice itching, redness or discharge with an unusual odor.

Chlamydia

Chlamydia, caused by the bacteria Chlamydia trachomatis, is a common STD that can lead to complications in both women and men. For women, if infection spreads to the uterus and fallopian tubes, it may cause pelvic inflammatory disease (PID), which can cause serious damage and infertility. It can also cause ectopic pregnancy, which is dangerous for both the mother and baby.

In men, if infection spreads to the urethra or anus, it may cause pain and tenderness in those areas. The infection can also cause epididymitis, which is an inflammation of the tube that carries sperm from the testicles to the reproductive organs.

If you have chlamydia, it’s important to get tested and treated right away. Treatment is simple and typically includes antibiotics taken by mouth. It’s also important to tell your anal, vaginal or oral sex partners that you have chlamydia so they can get tested and treated, too. This can help prevent them from developing serious symptoms and infections.

Gonorrhea

Gonorrhea is one of the most common sexually transmitted infections in the United States. It can cause serious health problems including infertility if untreated, but it is also usually easily treated with medicine. Gonorrhea can infect any part of the body in males or females but is more common in men. It can infect the throat (called pharyngeal gonorrhea) and the rectum or anus (called anal gonorrhea). It can also infect the testicles.

Symptoms of gonorrhea in men include itching, redness or discharge from the penis, white, yellow or green discharge from the urethra, or pain or burning when you pee (dysuria). People assigned male at birth—including cisgender men, transgender men and nonbinary people with penises—are more likely to experience these symptoms.

Gonorrhea is usually diagnosed by a healthcare professional swabbing the penis, vagina or throat for fluid to test for the infection. If you get a positive diagnosis, it’s important to tell your current sexual partners right away.

Viral Hepatitis

Hepatitis is a viral infection that causes swelling of the liver. There are five types of hepatitis: hepatitis A, B, C, D, and E. They are spread differently and can lead to different symptoms. Some kinds of hepatitis go away on their own, while others are life long and can cause serious health problems, including liver failure.

You can get hepatitis A from eating food and drinking water that have been contaminated with an infected person’s feces. It’s also common to spread hepatitis A through unprotected sex and sharing needles for injecting drugs. Hepatitis A is less common than hepatitis B or C, but it can still spread easily.

Hepatitis C is a very serious problem, with an estimated 396 million people infected worldwide. It can lead to liver disease, cancer and death. Hepatitis C can be spread through sex, sharing needles, unsafe injections and exposure to sharp instruments in health care settings, and from mother to child during vaginal birth.

Herpes

Herpes is a viral infection that typically causes painful sores or blisters on the lips, gums, and mouth. Blisters may be accompanied by fever, swollen glands, and fatigue. Herpes can be spread through nonsexual kissing or by sharing utensils or lip balm with someone who has herpes. Herpes can also be triggered by physical injury or surgery, menstruation, suppression of the immune system, and emotional stress.

Symptoms of genital herpes usually appear 2 to 3 days after exposure. They include a tingling sensation and a cluster of small red bumps that develop into itchy blisters. The blisters burst and are then replaced by dry, crusty skin. Some people have no symptoms and can only be diagnosed by a doctor who swabs the genital area.

Many STIs have no obvious symptoms, and it’s easy to mistake them for other problems. That’s why it’s important to get tested regularly, especially after unprotected sex. Testing is quick, easy, and confidential.