Overview

Oral thrush, also known as oral candidiasis, is a fungal infection of the mouth caused by an overgrowth of the Candida species, most commonly Candida albicans. It appears as white, creamy patches on the tongue, inner cheeks, gums, tonsils, or the roof of the mouth. Oral thrush is particularly common in infants, older adults, individuals with weakened immune systems, and those who use certain medications. Although it is generally a mild and treatable condition, it can cause discomfort, pain, and difficulty eating or swallowing. Prompt treatment usually leads to full recovery.

Causes

Oral thrush occurs when the balance of microorganisms in the mouth is disrupted, allowing Candida to multiply excessively. Common causes and risk factors include:

• Weakened immune system: Individuals with HIV/AIDS, cancer, or those undergoing chemotherapy are more susceptible.
• Antibiotic use: Broad-spectrum antibiotics can disrupt the natural balance of bacteria in the mouth, promoting fungal overgrowth.
• Corticosteroid use: Inhaled corticosteroids for asthma or oral corticosteroids can increase the risk of thrush, especially without proper mouth rinsing after use.
• Diabetes: Poorly controlled diabetes can lead to high sugar levels in saliva, encouraging fungal growth.
• Dry mouth (xerostomia): Reduced saliva flow increases the risk of oral infections.
• Dentures: Ill-fitting or unclean dentures provide a breeding ground for Candida.
• Infancy and old age: Infants and older adults have less robust immune defenses, making them more prone to oral thrush.
• Smoking: Tobacco use is associated with an increased risk of developing oral thrush.

Symptoms

The primary symptom of oral thrush is the presence of distinctive white or creamy patches in the mouth. Other symptoms include:

• White lesions: Soft, slightly raised patches on the tongue, cheeks, gums, tonsils, or throat that may resemble cottage cheese.
• Redness or soreness: The tissues underneath the white patches can be red, irritated, and painful, especially after scraping.
• Burning sensation: Some individuals experience a burning feeling in the mouth or throat.
• Cracking at the corners of the mouth: Also known as angular cheilitis, causing redness and soreness at the mouth’s corners.
• Loss of taste: Altered or reduced taste sensations are common.
• Difficulty swallowing: Severe cases can cause pain or difficulty swallowing (odynophagia).
• In infants: Fussiness, poor feeding, and white patches in the mouth are typical signs.

Diagnosis

Diagnosis of oral thrush is usually clinical, based on the characteristic appearance of lesions. Diagnostic methods include:

• Physical examination: A healthcare provider examines the mouth for white patches and signs of redness or inflammation.
• Microscopic examination: A gentle scraping of a lesion may be examined under a microscope to identify Candida organisms.
• Culture tests: In some cases, a culture may be taken to determine the exact species of Candida.
• Blood tests: May be ordered if an underlying condition like diabetes or immune deficiency is suspected.

Most cases of oral thrush are diagnosed easily without the need for invasive tests.

Treatment

Treatment of oral thrush focuses on eliminating the Candida overgrowth and addressing any underlying causes. Options include:

• Topical antifungals: First-line treatments such as nystatin suspension or clotrimazole lozenges are commonly prescribed for mild to moderate cases.
• Oral antifungal medications: Fluconazole or itraconazole may be used in severe or resistant cases, especially in immunocompromised individuals.
• Good oral hygiene: Brushing teeth twice daily, flossing, and rinsing the mouth after using inhalers help prevent recurrences.
• Denture care: Regular cleaning and proper fitting of dentures are crucial in denture wearers.
• Managing underlying conditions: Better control of diabetes or discontinuation of offending medications (under medical advice) can reduce recurrence risk.
• Dietary adjustments: Reducing sugar intake may help minimize fungal growth in some individuals.

In infants, thrush usually resolves with topical antifungal treatment and improved bottle or pacifier hygiene.

Prognosis

The prognosis for oral thrush is generally excellent, especially with timely and appropriate treatment. Key points include:

• Full recovery: Most healthy individuals recover completely within one to two weeks of starting treatment.
• Risk of recurrence: Thrush can recur, particularly in individuals with risk factors like immunosuppression, uncontrolled diabetes, or ongoing corticosteroid use.
• Chronic cases: People with weakened immune systems may experience recurrent or chronic thrush requiring long-term management.
• No serious complications: In most cases, oral thrush is not dangerous but can cause significant discomfort if untreated.
• Preventive care: Good oral hygiene, controlling medical conditions, and avoiding risk factors help prevent recurrence.

Overall, oral thrush is a manageable condition with high treatment success rates, particularly when underlying risk factors are addressed.