Thrush is caused by the Candida albicans fungus.

Candida albicans

Many people have a small amount of this fungus in their bodies. However, it does not usually cause problems because it is kept under control by the body’s immune system and other harmless bacteria (so called ‘good bacteria’).

Thrush can develop when the good bacteria in your body (which keeps candida under control) is destroyed. For example, if you are taking antibiotics to treat an infection, the antibiotics will not distinguish between good and bad bacteria, and will fight off both types.

Also, if you are run down and your immune system is weak, the candida fungus that causes thrush may multiply.

Personal hygiene

Candida tends to grow in warm and moist conditions. Therefore, you may develop thrush if you do not dry your penis carefully after washing.

Using perfumed shower gels and soaps can irritate your penis, making thrush more likely to develop. Candida also thrives on skin already damaged.

HIV, diabetes and other conditions

Men who have HIV, diabetes or other conditions that weaken the immune system are more at risk of developing thrush. This is because the infection develops quickly and the weakened immune system is not strong enough to fight it off.

If you have uncontrolled diabetes (usually because you do not realise that you have the condition), you are more likely to develop thrush. Typical signs of diabetes include:

• excessive thirst
• frequently need to pass urine
• weight loss

See your GP if you have these symptoms, or if you have thrush that keeps recurring (coming back), even after treatment.

If you have a weakened immune system there is a risk that the candida fungus will spread into your blood.

This is known as invasive candidiasis.

Invasive candidiasis

The infection can then spread quickly throughout your body affecting many of your organs. Known risk factors for invasive candidiasis include:

• having HIV
• having type 1 or type 2 diabetes
• taking immunosuppressants – a type of medication used to stop the body rejecting newly donated organs
• undergoing high-dose chemotherapy or radiotherapy
• having a central venous catheter (CVC) – a tube directly implanted into your chest and used to administer medication; they are often used in order to avoid repeated painful injections during a long-term course of medication
• having dialysis – a type of treatment where a machine is used to replicate the functions of the kidney and commonly used to treat kidney failure

Symptoms of invasive candidiasis can be wide ranging, depending on what part of the body is affected by infection. However, initial symptoms can include:

• a high temperature (fever) of or above 38ºC (101.4ºF)
• shivering
• nausea
• headache

Get medical help immediately if you have thrush and any of the risk factors listed above, and you develop any of the above symptoms over a short period of time.

Invasive candidiasis is a medical emergency that requires immediate admission to an intensive care unit (ICU). In an ICU,  functions of the body can be supported while the underlying infection is treated with anti-fungal medications.

If you are thought to be particularly vulnerable to invasive candidiasis – for example, you have diabetes and on dialysis, your GP may recommend you are admitted to hospital as a precaution if you develop a thrush infection.

Visit your GP if you think you have the symptoms of thrush (either on your penis or skin) and you do not have a history of the condition.

This is because there may be underlying factors that need further investigation. For example, you may have undiagnosed diabetes. Alternatively, your symptoms may be caused by something other than thrush, such as a bacterial skin infection.

If you have a previous history of thrush that has been diagnosed, you usually do not need another diagnosis unless it fails to respond to treatment.

Thrush can be diagnosed by your GP or by visiting your nearest local sexual health or genito-urinary medicine (GUM) clinic. Find a clinic.

Your GP or a doctor at the GUM clinic can confidentially diagnose thrush by physically examining the head of your penis or the affected area of skin.

Further testing is usually only required if:

• your symptoms are severe
• your symptoms persist despite treatment
• you have recurring episodes of thrush

Testing usually involves using a swab (a small plastic rod with a cotton ball on one end) to obtain a small tissue sample from the affected body part. The tissue will be tested for the presence of any infectious agents, such as the Candida albicans fungus.

You may also be referred for a series of blood and urine tests to check whether an underlying condition, such as diabetes, is making you more vulnerable to thrush.

Recurring thrush

If you have had thrush in the past and you recognise your symptoms, over-the-counter treatments from your pharmacist can help clear up the infection.

If you keep getting thrush, or it does not clear up with treatment, visit your GP so they can investigate and recommend appropriate treatment.

If you are a heterosexual man and have thrush, it is likely your partner may also have the condition. This is because the candida fungus often lives inside the vagina. It is therefore a good idea for both of you to get treatment in order to prevent the infection being passed back and forth between you.

Thrush is a yeast infection caused by a fungus called Candida albicans. Both men and women can get thrush though it is more often associated with women.

The medical term for thrush is candidiasis.

What it looks like

In men it usually affects the head of the penis causing inflammation, a smelly lumpy discharge, and pain while passing urine. Read more about the symptoms of thrush.

It can also affect the skin, known as candidal skin infection, and the inside of the mouth, known as oral thrush.

Should I see a doctor?

If you suspect thrush for the first time it’s best to see a doctor for a diagnosis.  This is because the symptoms can be similar to those of a sexually transmitted infection (STI).  Your GP will be able to tell the difference.

If you’ve had thrush before and you recognise the symptoms, you can treat it yourself with over-the-counter medication.

You should also visit your GP if you have a weakened immune system and you have thrush. This is because there is a risk that a thrush infection could progress to a more serious case of invasive candidiasis. See complications of thrush  for more information.

Treating and preventing thrush

You can treat thrush without prescription medications. For thrush affecting your penis ask your chemist for a tablet called fluconazole. For thrush infections in your groin or elsewhere the chemist can supply a cream or ointment.

It is possible for thrush to spread during sex, but it is not a sexually transmitted infection (STI). However both sexual partners may need thrush treatment to prevent re-infection. Re-infection from a female partner is common. Seek advice about this from a pharmacist or your GP.

Not all cases are caused in this way and many cases develop in men and women who are not sexually active.

Read more about treating thrush.

You can help prevent thrush by cleaning your penis regularly and using a condom while having sex with your partner (if they have thrush).

Avoid using perfumed shower gels or soaps on your genitals, as they can cause irritation. Make sure you dry your penis properly after washing.

Wearing loose-fitting cotton underwear can help prevent moisture building up under your foreskin, which lowers the chances of the candida fungus multiplying. 

What causes thrush?

The fungus candida albicans occurs naturally in your body, particularly in warm, moist areas, such as inside the mouth and around the genitals.

It does not usually cause problems because it is kept under control by your immune system (the body’s natural defence against illness and infection) and other types of bacteria in the body.

However, certain conditions can cause the fungus to multiply and lead to infection. You are more likely to be at risk of thrush if:

• you have a weakened immune system
• are obese, with large rolls of skin (an environment where fungi can often thrive)
• have type 1 diabetes or type 2 diabetes – as the high levels of glucose associated with diabetes can encourage the fungus to breed; also, people with diabetes tend to sweat more creating a perfect breeding environment for the fungus

Read more about what causes thrush in men.

If you have balanitis thrush, you will have a number of distinctive symptoms.

You symptoms are likely to include:

• red skin around the head of the penis
• swelling of the head of the penis
• irritation and soreness of the head of the penis
• thick, lumpy discharge under the foreskin
• itchiness around the head of the penis
• an unpleasant odour
• difficult retracting (pulling back) the foreskin of your penis (phimosis)
• pain when passing urine
• pain during sex

Thrush as a skin infection

Most candidal skin infections develop in areas of the body where folds of skin come together, such as the:

• armpits
• groin
• areas between your fingers
• skin between your genitals and anus (the opening where faeces are expelled from the body)

People who are obese are also at risk of developing a skin infection between their rolls of skin.

The infection usually begins as a red and painful itchy rash. Small red spots can also develop on the rash. Affected skin may then scale over, producing a white-yellow curd-like substance. If the skin between your fingers is affected, it becomes thick, soft and white.

The recommended first-line treatment for thrush in areas apart from the penis is a type of anti-fungal cream called topical imidazole.

Topical imidazoles work by breaking down the membranes (walls) of the fungi cells.

Examples of topical imidazoles include:

• clotrimazole
• econazole
• ketoconazole
• miconazole

Most of these are available from your pharmacist without a prescription. Your pharmacist can advise which treatment is most suitable for you.

The most common side effect of a topical imidazole is a mild burning sensation when you apply the cream.

In a few people, some topical imidazoles have caused more severe burning and a serious skin irritation. If this happens, stop using the cream and contact your GP for advice.

If you are having symptoms of itchiness, your GP may prescribe a corticosteroid cream as an additional treatment. Corticosteroids reduce levels of inflammation within the affected tissue. This should help resolve the symptoms of itchiness.

Doctors report re-infection is common so during treatment it is best to avoid sex or use a condom. Occasionally both sexual partners may need treatment to prevent re-infection. Seek advice about this from a pharmacist or your GP.

Fluconazole

If your symptoms do not improve within 14 days, you may need an alternative antifungal medication. Fluconazole taken in tablet form is the preferred treatment. Fluconazole is also the first choice treatment for treating thrush which affects the penis. Most products that contain fluconazole are available over-the-counter (OTC) without a prescription.

Fluconazole works by destroying some of the enzymes (a type of protein that triggers useful chemical reactions inside the body) that fungi cells need to survive and reproduce.

The most common side effects of fluconazole are:

• nausea
• abdominal (tummy) pain
• diarrhoea
• flatulence (excessive wind)

Contact your GP for advice if your symptoms do not improve after 14 days of taking fluconazole. You may need to be referred to a dermatologist for specialist treatment. A dermatologist is a doctor who specialises in treating skin conditions.

Good hygiene

If you have thrush, practising good personal hygiene can help clear up the infection. Wash the affected area carefully using warm water. Showers are a better option than baths. Avoid using perfumed shower gels or soaps on your genitals because they can cause irritation.

After washing, make sure you dry the affected area carefully as the candida fungus thrives in damp conditions. Wearing loose-fitting cotton underwear can help keep your skin and penis dry and cool, which helps prevent build-up of the candida fungus on your skin and under your foreskin.