Fungal infections

A fungal infection happens when a fungus grows out of control on or in your body, often because your immune system cannot keep it in check. Most fungal infections affect your skin, nails or mouth and are not serious, although infections deeper in the body can be more severe.

Symptoms of a fungal infection

Your symptoms depend on where the infection is and what is causing it. On your skin, nails or in your mouth, you might notice:

• itching, soreness, redness or a rash
• discoloured, thickened or cracked nails
• scaling, cracking or peeling skin
• a painless lump under your skin
• white patches in your mouth or throat.

If a fungal infection affects your lungs or another part of your body, you may have:

• a cough, sometimes with blood
• tiredness, fever or night sweats
• shortness of breath
• muscle aches, joint pain or headache.

Causes of fungal infections and who is at risk

Fungi live all around us - in the air, soil and water, and on our skin, and most are completely harmless. Out of the millions of fungal species that exist, only around 300 are known to cause illness in people.

Some fungal infections happen when a fungus that's already on your body, such as Candida, grows out of control. Others spread through direct contact with an infected person or animal, contaminated surfaces such as shower floors, or by breathing in fungal spores from soil or dust.

You may be more likely to develop a fungal infection if you:

• have a weakened immune system, for example due to HIV, cancer treatment or an organ transplant
• have diabetes or poor circulation
• are taking antibiotics, steroids or other medicines that affect your immune system
• spend time in warm, moist environments, such as showers, swimming pools or locker rooms
• have areas of skin that stay warm and moist, such as your feet, groin or skin folds.

Are there different types of fungal infection?

Fungal infections are generally grouped by how deep they go:

• superficial infections affect your skin, nails or mucous membranes, such as your mouth or vagina, and include athlete's foot, ringworm, jock itch, oral thrush and vaginal yeast infections
• subcutaneous infections develop under the skin, usually after a cut or wound, and are more common in tropical parts of the world
• deep or invasive infections affect internal organs such as your lungs, brain or blood, and are more likely if you have a weakened immune system.

How fungal infections are diagnosed

How a fungal infection is diagnosed depends on where it is. Many skin infections, such as athlete's foot, ringworm or jock itch, can be identified just by how they look.

Your doctor may take a small sample, such as a skin scraping, nail clipping or swab, to examine under a microscope or send for culture. If a deeper infection is suspected, for example in your lungs or brain, you may need blood tests or a scan, such as an X-ray, MRI or CT scan.

How fungal infections are treated

Most fungal infections are treated with antifungal medicine, which comes in different forms depending on where the infection is. These include creams, ointments or powders for your skin, tablets or liquid medicine you swallow, shampoo, mouthwash, eye drops, or medicine given directly into a vein for more serious infections.

Antibiotics do not work on fungal infections, so it's important to get the right diagnosis before starting treatment. Some antifungal treatments are available over the counter, but it's worth checking with a pharmacist or doctor first, especially if your symptoms don't improve or keep coming back.

When to see a doctor

See a doctor or pharmacist if you think you have a fungal infection, particularly if you're not sure what's causing your symptoms. Fungal infections don't usually clear up on their own and can spread or get worse if left untreated.

You should also get advice if:

• your symptoms don't improve with over-the-counter treatment
• you have symptoms affecting your lungs or another organ, such as a persistent cough, fever or shortness of breath
• you have a weakened immune system and develop new symptoms
• an existing infection keeps coming back.