Oral Candidiasis (Oral Thrush)

Symptoms

• creamy white or yellowish patches on the tongue, inner cheeks, roof of the mouth, gums or tonsils, like cottage cheese
• red, raw areas left when patches are wiped off, sometimes bleeding slightly
• soreness or burning, especially with spicy or acidic food
• a cottony feeling in the mouth
• loss of taste or a bad taste
• cracking and redness at the corners of the mouth (angular cheilitis)
• in babies: white patches, fussiness during feeds, and sometimes a yeast diaper rash

Types

Causes and risk factors

Candida normally lives in the mouth in small numbers. Thrush develops when the balance shifts:

• infancy: immature immune systems; may pass between baby and breastfeeding parent
• dentures, especially worn overnight or poorly cleaned
• inhaled corticosteroids for asthma or COPD without rinsing afterward
• antibiotics, which reduce competing bacteria
• dry mouth (xerostomia) from medicines, Sjögren's syndrome or radiation
• diabetes, especially if poorly controlled
• weakened immunity: HIV, chemotherapy, transplants, oral steroids
• smoking
• iron, folate or B12 deficiency

Thrush vs other white patches

• milk residue in babies wipes off easily without leaving redness
• leukoplakia does not wipe off and may be precancerous
• oral lichen planus forms lacy white lines
• hairy leukoplakia on the sides of the tongue, linked to Epstein-Barr virus in immunosuppression
• geographic tongue has shifting map-like red patches with white borders

Diagnosis

Usually diagnosed by appearance. A scraping can be examined under a microscope or cultured, especially for recurrent or treatment-resistant cases. Blood tests may check for diabetes, anemia or HIV when there is no clear cause.

Treatment

Topical treatment (mild cases)

• nystatin suspension swished and swallowed several times a day
• miconazole oral gel or buccal tablet (not for babies under 4 months without medical advice because of choking risk)
• clotrimazole troches (lozenges) dissolved in the mouth

Treatment usually lasts 7 to 14 days and continues for a couple of days after symptoms clear.

Oral tablets

Fluconazole for moderate to severe thrush, people with weakened immunity, or esophageal involvement. Some medicines interact with fluconazole, so tell your doctor what you take.

Treating babies and breastfeeding parents

Babies are treated with nystatin or miconazole gel. If breastfeeding, the parent's nipples may also need antifungal cream if they are sore, to avoid passing the infection back and forth. Sterilize bottle nipples and pacifiers.

Supportive measures

• rinse your mouth with water and spit after using steroid inhalers, or use a spacer
• remove dentures at night, clean them daily and soak in a denture cleanser
• brush teeth and tongue gently twice a day
• control blood sugar
• treat dry mouth and stop smoking

Complications

In people with healthy immune systems, thrush is rarely serious. In those with weakened immunity, it can spread to the esophagus (esophageal candidiasis), causing painful swallowing, and rarely into the bloodstream.

Frequently asked questions

What causes oral thrush in adults?

Common causes are dentures, inhaled steroid use without rinsing, recent antibiotics, dry mouth, diabetes and smoking. Thrush without an obvious cause can be a sign of a weakened immune system, so a doctor may check for diabetes or HIV.

How do you get rid of oral thrush fast?

Antifungal treatment, such as miconazole gel, nystatin or clotrimazole lozenges, usually improves thrush within a few days. Fluconazole tablets work quickly for more severe cases. Keeping dentures clean and rinsing after inhalers help prevent it coming back.

Is oral thrush contagious?

It is not usually considered contagious between healthy adults, because Candida already lives in most people's mouths. However, it can pass between a baby and a breastfeeding parent, and through shared pacifiers or bottles.

Can oral thrush go away on its own?

Mild thrush in babies sometimes clears on its own, and mild cases after antibiotics may resolve. However, treatment is usually recommended because it is quick and effective, and untreated thrush can spread or keep returning.