What can male discharge from an STI look like?

Sexually transmitted infections (STIs) are infections that most people contract through sexual activity. Most STIs are transmitted through vaginal, anal, and oral sex, or by sharing sex toys. Infected bodily fluids come into contact with the mucous membranes of the genitals, eyes, rectum, and throat, leading to infection.

However, you don’t have to have full sexual intercourse to get an STI. Some infections can spread in other ways.

Bloodborne infections, like HIV, Hepatitis B, and Syphilis, can all be transmitted through things like blood transfusions, needle stick injuries, and using unsterilised tattooing equipment. You can also get infections like HPV and Herpes through skin-to-skin contact.

“Discharge,” in this context, applies to substances that are secreted from the inside of male genitalia. It comes out of the tube your urine comes out of.

However, “discharge” doesn’t apply to things like semen and urine – natural substances prompted by normal bodily processes.

The problem comes when the discharge in question arrives unprompted or in scenarios where you wouldn’t normally secrete something.

So, if something is coming from your genitals, and it isn’t a normal substance like urine, semen, or sweat, you may want to get it checked out. It could be an STI. Have a look at any liquid, but also look at your underwear – it can be the best place to see what’s been happening during the day and if there is a persistent discharge occurring.

Penile discharge caused by STIs tends to be caused by bacterial infections that infect the urinary tract. These bacteria hunker down mostly in your urethra, but occasionally they will move up into the prostate or even the testes. The immune response to these infections usually causes inflammation, pus, and plasma to secrete from the tip of your penis.

Here is a list of STIs and what the discharge from the penis may look like.

(NOTE: It’s notoriously difficult for doctors to guess correctly which infection is which just from the appearance of discharge, so testing is always the best option, looking for all possible culprits at the same time.)

Chlamydia

Chlamydia is the world’s most common bacterial STI. This infection is especially pernicious because it’s so good at going undetected. Around 75% of women and 50% of men who get Chlamydia don’t experience any symptoms.

However, when symptoms do appear, they can include discharge. When men have a Chlamydia infection, the discharge can be just a single drop of clear sticky fluid, or be white, cloudy, watery, or even creamy. The discharge may have a foul smell.

Gonorrhoea

The runner-up in the common bacterial STI competition is Gonorrhoea. While less common than Chlamydia, it can cause just as much damage to your sexual health if left untreated. And like Chlamydia, it’s often difficult to know you have it since symptoms can go undetected.

Discharge is an extremely common symptom of Gonorrhoea. However, the discharge caused by Gonorrhoea is a slightly different hue. This abnormal penile discharge shades from green, yellow, and white and is mucopurulent (meaning it contains both mucus and pus). However, remember that in early infections or those with few bacteria there may be just one small drop of cloudy fluid.

Trichomonas

Trichomonas is a different beast from the mangy microbes listed above. Unsatisfied with fitting in, this infection is caused by a parasite rather than a bacteria. However, like the above infections, the protozoans infect the urinary tract, causing similar symptoms, including discharge.

However, the discharge created by this infection is unique. It tends to be white, thin in consistency, and slightly watery. A distinctive “fishy” smell may accompany it. Remember that any discharge, including that of trichomonas may be in very small amounts.

Mycoplasma

This bacterial infection is less common than Chlamydia or Gonorrhoea but causes many of the same symptoms. As such, the discharge caused by Mycoplasma can resemble both that of Chlamydia and Gonorrhoea, but it typically scarcer in quantity.

Ureaplasma

Ureaplasma occupies an interesting place in the world of STIs. Unlike the infections listed above, Ureaplasma naturally occurs in the respiratory, urinary, and reproductive tracts of both men and women. An infection occurs when the bacteria overgrow and cause symptoms. This infection can also be sexually transmitted.

Ureaplasma infections are relatively common in men. About 70% of all sexually active individuals will test positive for a Ureaplasma infection. However, most people don’t even know they have it. When symptoms do occur, the discharge caused is similar to that caused by Chlamydia.

Herpes

Herpes is the outlier on this list.

While all the above infections infect the urinary tract, Herpes is a virus that infects the area around the genitals and mouth.

The virus embeds itself around the nerve endings of these areas. Periodically, the virus travels to the surface of the skin, causing outbreaks of blisters that can be painful and itchy. Eventually, these blisters burst, releasing a clear, watery fluid.

It is therefore the presence of lesions on the skin or unpleasant pain that points to possible Herpes.

While STIs can often cause discharge from the penis, there can also be other causes.

NSU

The bacteria that cause urinary tract infections (UTIs) in men can also directly infect the urethra, leading to penile discharge due to inflammation. The infection causes irritation, resulting in a cloudy or milky discharge. This is often accompanied by symptoms like burning during urination and frequent urges to urinate. We call this NSU (non specific urethritis), and although it seems identical to an STI like Chlamydia or Gonorrhoea, the underlying bacteria are just the ones that got inside during sex.

Prostatitis

Prostatitis, an inflammation of the prostate gland, can cause penile discharge in men. The inflammation of the prostate can spread to the urethra, leading to irritation and resulting in a discharge that is typically transparent and sticky. It tends to be confused with pre-ejaculate. Sometimes it can be much more marked, and looks like pus. This condition is often accompanied by symptoms such as pain during urination, pelvic discomfort, and difficulty urinating.

Balanitis

Balanitis, an inflammation of the head of the penis, can also cause a liquid that men confuse with discharge. This condition occurs when the sensitive skin on the glans becomes irritated, often due to infections, poor hygiene, or an allergic reaction. The irritation can lead to redness, swelling, and a discharge that might be whitish or yellow. Other symptoms may include itching, pain, and discomfort during urination. Itching is common too. However, it’s not a true discharge as the liquid is not produced inside the body.

Smegma

Smegma, a natural substance made up of dead skin cells, oils, and moisture, can lead to a noticeable buildup under the foreskin in uncircumcised men. This accumulation may appear as a white, cheesy substance and can sometimes cause a mild discharge. While not an infection, and also not truly a discharge, smegma can lead to irritation, redness, or an unpleasant odour if not cleaned regularly.

Pre-ejaculate

Pre-ejaculate, also known as pre-cum, is a clear fluid released from the penis during sexual arousal. Unlike other discharges, it’s a natural lubricant produced by the Cowper’s glands, located near the base of the penis. This fluid helps to neutralize the acidity in the urethra, creating a safer environment for sperm during ejaculation.

Discharge from your genitals can be a distressing symptom to experience. If you think your discharge may be caused by an STI, you should get tested.

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This article has been medically reviewed by Dr. Steve Chapman, 30/10/2024.