Signs that your rash may be a sexually transmitted infection (STI) include genital discharge or swelling, blisters, pain when peeing, and other symptoms in the anal area. See a doctor for proper diagnosis and treatment.

If you’re worried that you or your partner may have contracted a sexually transmitted infection (STI), read on for the information you need to recognize the symptoms.

Some STIs have no symptoms or only mild ones. If you’re concerned but don’t see symptoms identified here, check with your doctor to discuss your STI risks and appropriate testing.

Discharge from the vagina

Small amounts of discharge, especially from the vagina, is often normal.

But some sexually transmitted conditions can cause discharge from the genitals. Depending on the condition, the color, texture, and volume of the discharge may vary.

Though many people with chlamydia don’t have symptoms, this condition sometimes produces a mucus- or pus-like vaginal discharge.

With trichomoniasis, or “trich,” the vaginal discharge looks frothy or foamy and has a strong, unpleasant odor.

A yellowish or yellow-green vaginal discharge can be a symptom of gonorrhea, although most people who contract it will have no symptoms at all.

Discharge from the penis

Some conditions can cause discharge or even bleeding from the penis.

Gonorrhea produces a white, yellow, or greenish discharge from the penis.

Chlamydia symptoms may include a pus-like discharge from the penis, or the fluid may be watery or milky-looking.

Trichomoniasis doesn’t usually show symptoms, but it can cause discharge from the penis in some cases.

HPV and genital warts

With the human papillomavirus (HPV), the body often naturally clears the virus. However, the body can’t remove all strains of HPV.

Some strains of HPV cause genital warts. The warts can vary in size and appearance. They can look:

  • flat
  • raised
  • large
  • small
  • cauliflower-shaped

All genital warts need medical attention. Your doctor will determine whether the warts are caused by the strains of HPV that may cause anogenital cancer.

Severe HPV may cause several warts in the genital or anal areas.

Herpes

Blisters on or around the genitals, rectum, or mouth may signal an outbreak of herpes simplex virus. These blisters break and produce painful sores, which can take several weeks to heal.

Herpes blisters are painful. There may be pain while urinating if the herpes blisters are close to the urethra.

It’s important to remember that herpes can still spread from one person to another, even if there are no visible blisters.

Granuloma inguinale

Granuloma inguinale usually starts with a nodule that erodes into an ulcer. The ulcer is usually painful.

Syphilis

A single, round, firm, painless sore is the first symptom of syphilis, a bacterial STI. The sore can appear wherever the bacteria entered the body, including the:

  • external genitals
  • vagina
  • anus
  • rectum
  • lips
  • mouth

One sore appears at first, but multiple sores may appear later. The sores are generally painless and often go unnoticed.

Secondary stage syphilis rash and sores

Without treatment, syphilis progresses to a secondary stage. Rashes or sores in mucous membranes of the mouth, vagina, or anus occur during this stage.

The rash may look red or brown, and have a flat or velvety appearance. It usually doesn’t itch.

The rash can also appear on the palms or soles of the feet, or as a general rash on the body. Large gray or white lesions may appear in moist areas in the groin, under the arms, or in the mouth.

Epididymitis is usually caused by an STI, like gonorrhea or chlamydia, or a urinary tract infection.

Epididymitis is the clinical term for pain and swelling in one or both testicles. People with penises who contract chlamydia or gonorrhea may experience this symptom.

Chlamydia can spread to the rectum. In these cases, symptoms may include:

  • prolonged rectal pain
  • painful bowel movements
  • discharge
  • rectal bleeding

Gonorrhea rectal symptoms include:

  • pain and itching in the anus
  • bleeding
  • discharge
  • painful bowel movements

Pain, pressure, or burning during or after urination, or more frequent urination, may be a symptom of chlamydia, trichomoniasis, or gonorrhea in people with a vagina.

Because gonorrhea in people with a vagina often produces no symptoms or only mild symptoms that can be confused with a bladder infection, it’s important not to ignore painful urination.

In people with a penis, either trichomoniasis or gonorrhea may cause painful urination. Pain after ejaculation may also occur in those who contract trichomoniasis.

Many STIs can be treated and cured, especially if diagnosed early.

If you’re experiencing any of the above symptoms, see a healthcare provider to get a diagnosis and appropriate treatment.