What STIs cause yellow discharge?

“Discharge” is a general term that refers to substances that are secreted unprompted from the genitals.

In women, vaginal discharge is a natural part of the vagina’s self-cleaning process. Vaginal discharge is usually made up of fluid and mucus that keeps the vagina clean and moist, and protects it from infection.

In men, discharge can include things like pre-ejaculate and ejaculate, which are released from the tip of the penis as a result of arousal and orgasm.

In some cases, vaginal discharge can be yellow, such as during menstruation or early pregnancy. Heavy flows of vaginal fluid, when they come in contact with the air, may take on a yellowish hue as a result of oxidation.

This is also the case with discharge experienced by men. Smegma, a secretion of skin and sweat that coagulates under the foreskin, can also oxidise when exposed to the air, giving it a yellowish tinge. However, as this doesn’t actually come from inside the urethra (the tube where we urinate) it is not technically discharge, although it may appear to be.

With that said, you’ll want to investigate if you’re experiencing unusual discharge (i.e., discharge you wouldn’t normally experience).

Certain STIs can cause yellow discharge from the genitals. You should consider getting tested if you’re experiencing any of the following symptoms.

Chlamydia, Gonorrhoea, and Mycoplasma genitalium

Chlamydia, Gonorrhoea, and Mycoplasma genitalium are bacterial STIs that infect the urinary tract. These infections often cause:

• Pain during sex
• Abdominal pain
• Pain during urination
• Discomfort and itching in the genital region
• An unusual discharge from the genitals that can be yellow, green, or white in colour

Both of these infections are notoriously difficult to confirm by symptoms alone. Most people who get Chlamydia or Gonorrhoea infections do not know that they have them. Getting tested is the only way to know you have one of these STIs.

Bacterial Vaginosis

While not technically an STI, Bacterial Vaginosis (BV) can be spread from person to person during sex.

BV can result from an overgrowth of Gardnerella bacteria in your vagina. While most people with an overgrowth of bacteria do not experience any symptoms, in women, it causes a discharge that can be yellow, grey, or green in colour with a consistency like cottage cheese.

Trichomonas

Unlike the above examples, Trichomonas is an STI caused by a parasite. During sex, this parasite sets up shop in your urinary tract, causing itching and discomfort in the genital area, and pain during sex and urination.

Another tell-tale sign of a Trichomonas infection is its discharge, which can be white, yellow, or green in colour, with a thin and frothy consistency. It also often has a foul, fish-like smell.

Yellow discharge isn’t only caused by STIs. Here are a few other conditions that may be causing it:

• Vaginitis: An umbrella term that’s used to describe several conditions that cause inflammation or irritation of the vagina, like yeast infections, some of which can cause some yellow discharge, although typically it’s white.
• Cervicitis: A condition where the cervix becomes inflamed caused by allergies or bacterial overgrowth.
• Trauma: Traumatic damage to a man’s urethra, such as a blow to the genitals, or damage inside caused by an STI like Chlamydia which has been cleared but which causes lasting trauma.
• A retained tampon or other foreign bodies
• Non-specific Urethritis: The inflammation of the urethra caused by bacterial infections.
• Prostatitis: a prostate infection may produce a bead of yellow pus, especially in the morning or when straining to pass stools

If there is an unusual discharge coming from your genitals, it may be an STI. Protect your sexual health by getting tested with Better2Know today.

Try our Comfort Screen, which tests for all the infections that tend to cause genital discharge. Click the button below to book your screen.

This article has been medically reviewed by Dr. Steve Chapman, 03/12/2024.