Is Thrush Contagious?

Thrush is an infection of the oral mucous membranes (inner lining of the mouth and tongue) by the fungus Candida albicans. Thrush is also termed oral thrush, oral candidiasis, and oropharyngeal candidiasis. Thrush infection is not very common in the healthy population. However, thrush can be present in about 5%-7% of babies less than 1 month old, in AIDS patients (about 9%-31%), and in approximately 20% of cancer patients.

Oral thrush, a fungal infection, is not considered contagious. The causative fungus, Candida albicans, is often already a natural inhabitant of the mouth and throat. When the oral environment changes (usually due to an immature or depressed immune system), the fungus can multiply and cause symptoms. Occasionally, individuals taking antibiotics or steroids (such as prednisone) can develop thrush. Although thrush is usually considered not to be contagious, one instance where the fungus can be passed back and forth is between infant and mother. An infant may develop thrush and transfer it to the mother's nipples, which become painful with reddish, cracking skin. Conversely, mothers may develop a Candida albicans yeast infection on their nipples while taking antibiotics or steroids and transfer the infection to their babies while breastfeeding. The incubation period for oral thrush is about two to five days.

Usually, the first common sign of thrush in adults and children is the presence of whitish raised oral lesions (sometimes resembling cottage cheese). The lesions can be on the tongue, the inside of the cheeks, on the gums, tonsils, or the back of the throat. It can be painful and bleed a little if they are scraped when touched or brushed with a toothbrush. Some people with thrush lose the sense of taste while others have a feeling of cotton in the mouth. Severe thrush can spread to the esophagus and cause fever, difficulty swallowing, and a feeling like something is caught in the throat. Severe thrush can spread to other parts the body such as the lungs, liver, and skin. Most thrush can be diagnosed by simply observing the characteristic lesions. Scrapings can be used to microscopically identify the fungus. In addition, fungal cultures can document Candida albicans.

In general, most of the population has some trace levels of Candida albicans on the mucous membranes of the mouth. Most the time, the fungus causes little or no problems unless there is a change in the mucous membranes, in a person's immune system, or from taking antibiotics or steroids. These situations allow the fungus to proliferate. Consequently, in most instances, there is no transfer from person to person of thrush. The major exception to this is with infants and their breastfeeding mothers, as they may transfer Candida albicans between each other.

In general, mild to moderate oral thrush infections are treated using antifungal mouthwash or lozenges. The treatment is usually for seven to 14 days. For severe thrush, it is advised to treat for twice as long as the symptoms last (for example, 28-42 days). More severe thrush symptoms and signs may persist for a greater length of time (for example, 14-21 days) before they resolve.

Contact your child's pediatrician immediately if your infant has any symptoms of thrush. If an adult individual has symptoms or signs of thrush, they should contact their physician for both care and an examination to determine what underlying causes might be leading to the development of thrush.

If after seven days of treatment, symptoms not improving or are getting worse, contact a physician. If you have an immune system that is suppressed or altered (HIV infection, cancer, breastfeeding, taking antibiotics) and develop symptoms of thrush, contact a doctor immediately.