Can an STI Cause Thrush?

Whilst thrush is not classed as a sexually transmitted infection, it can be triggered by and passed on through sex. Pre-existing illnesses and health problems may trigger thrush, however, STIs are not usually the cause. 

In this blog we take a look at thrush and see how the symptoms can sometimes be similar to those caused by STDs. 

thrush legs in the air

What is Thrush?

Thrush, otherwise known as a yeast infection, most commonly occurs in women, although can also affect men. It is usually harmless, but can be uncomfortable, irritating and may recur, even if treated. Whilst thrush most commonly affects the genitals, it can also affect other areas such as the armpit, the mouth, and between the fingers.

What are the Symptoms of Thrush?

Symptoms of thrush and their severity will vary from person to person, however common symptoms in men and women include the following.

Symptoms of thrush in women:

  • A thick, white vaginal discharge (this often resembles cottage cheese)
  • Discomfort, itching and irritation around the vagina
  • Soreness and stinging when you pee or during sex
  • Redness, swelling or splits in the skin around the genitals

Symptoms of thrush in men

  • White discharge (this often resembles cottage cheese)
  • Irritation, burning and redness around the head of the penis and under the foreskin
  • Difficulty pulling back the foreskin
  • An unpleasant smell

Do I Have Thrush or an STI?

As 75% of women will experience thrush in their lifetime, it can be easy to self-diagnose symptoms as thrush. However, there are various STIs that have similar symptoms to thrush, and are often misdiagnosed as such, including:


The symptoms of thrush and chlamydia can be very similar, including irritation, discharge and pain when peeing. If you have chlamydia, you may also develop abdominal pain and urinary tract infections (UTIs).


A key difference between thrush and gonorrhea is the appearance of discharge. In thrush, discharge tends to be thick and white, often resembling cottage cheese. Discharge caused by gonorrhea, however, tends to be on the yellow side.


The symptoms of Trichomoniasis are very similar to that of thrush. You may experience vaginal discharge (this may appear white, grey or yellow in colour), genital redness and irritation, and pain when urinating or during sexual activity. If you are sexually active, it is recommended that you are tested regularly for STIs, particularly if the symptoms could be mistaken for something else. 


Often, the symptoms of genital herpes are so mild that you may not know that you have it. However, should symptoms develop, you may experience pain and irritation in the genital area, which is also common with thrush. However, the most prominent sign is small bumps and blisters, ulcers and scabs, which are not common with thrush.

The only way to know if you have an STD is to get tested

If thrush treatment is unsuccessful after the advised treatment period, and you have been recently sexually active, it is important to be tested for STIs. Left unchecked, STIs can cause serious health problems further down the line. Check out the Your Sexual Health website for a wide range of tests that can be taken in the privacy of your own home. 

What Causes Thrush?

Thrush is usually caused by an imbalance or overgrowth of the yeast Candida Albicans. This naturally lives in the bowel and vagina, but will occasionally become unbalanced due to a number of reasons:

  • Use of antibiotics
  • Use of oral contraceptives
  • Changes in the menstrual cycle
  • Pregnancy
  • Other illnesses such as diabetes, anemia and immune system disorders

Thrush is usually harmless and is nothing to worry about. Around 75% of women will have vaginal thrush in their lifetime. However, if you suspect you have thrush for the first time, it is recommended that you contact your GP.

Although not classified as an STI, thrush can sometimes be passed on via sex, and sexual activity can make symptoms worse. 

How is Thrush Treated?

If you are under 16 or over 60, have a weakened immune system, are pregnant, thrush keeps recurring, or you are experiencing thrush for the first time, it is recommended that you see a GP or visit a sexual health clinic. 

Usually, thrush is treated with an antifungal medication. This will be in the form of an oral tablet, a cream or a pessary. Symptoms should begin to clear within 7-14 days of treatment. 

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