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Oral candidiasis, also known as oral thrush, is a fungal infection caused by the fungus Candida albicans when the body’s defenses are low or the balance of the oral microbiota is disturbed, allowing its uncontrolled proliferation on the oral mucosa.
Oral candidiasis is frequently confused with normal irritation or spots, which delays diagnosis. Without treatment, the infection spreads, becomes chronic, and can become a warning sign of an underlying undiagnosed immunodeficiency. Identifying it in time and treating the predisposing factor is the only way to avoid recurrences.
At Asensio Dental Clinic, Dr. Lucía Asensio Romero (Registration No. 46002287), a specialist in oral medicine in Valencia, diagnoses and treats oral candidiasis with protocols adapted to each patient profile. The first visit is completely free.
Symptoms of oral candidiasis
The most characteristic symptom of oral candidiasis is the appearance of creamy white plaques on the tongue, palate, inner cheeks, or gums. These plaques have the appearance of cottage cheese and can be scraped off with gauze, leaving a reddened and sometimes bleeding surface. Their presence is almost diagnostic on its own, although it should always be confirmed with clinical examination and, when in doubt, with a microbiological culture.
Other common symptoms include a burning or stinging sensation in the mouth — especially when eating acidic or spicy foods —, difficulty swallowing, loss or alteration of taste, and dry mouth. In some patients, the pain is so intense that it interferes with eating and produces unintended weight loss.
There are several clinical forms of oral candidiasis with different presentations. Acute pseudomembranous is the most frequent and presents the characteristic white plaques. The erythematous or atrophic form presents as red and painful areas without visible plaques, and is especially common in denture wearers — what is colloquially known as prosthetic stomatitis. Angular cheilitis, with fissures at the corners of the lips, can also have a candidal origin, especially in patients with iron or B-group vitamin deficiencies. Chronic erythematous candidiasis appears on the palate of smokers as a bright red area.
Causes and risk factors for oral candidiasis
Candida albicans is part of the normal microbial flora of the mouth in approximately 50% of healthy people. Its presence does not imply disease: infection only occurs when the balance between the fungus and the host’s defenses is broken in favor of the fungus. Understanding the factors that favor this imbalance is essential to prevent recurrences.
Prolonged use of broad-spectrum antibiotics eliminates the bacteria that compete with Candida, allowing its proliferation. Inhaled corticosteroids — used in asthma treatment — are deposited on the oral mucosa and create a propitious environment for fungal growth, especially when the patient does not rinse their mouth after use. Xerostomia or dry mouth, produced by medications, head and neck radiotherapy, or Sjögren’s syndrome, eliminates the protective action of saliva on the mucosa.
Ill-fitting dentures or poor denture hygiene creates spaces between the prosthesis and the mucosa where Candida accumulates without access to salivary flow. Uncontrolled diabetes — with elevated glucose levels in saliva — creates an ideal culture medium for the fungus. Immunosuppression due to HIV, organ transplant, chemotherapy, or treatment with immunosuppressants eliminates the defense mechanisms that keep Candida under control. If you are undergoing oncological treatment, consult our special needs patient care page.
Treatment of oral candidiasis
The treatment of oral candidiasis is fundamentally pharmacological and has very high efficacy when applied correctly and the predisposing factor is eliminated. The antifungal of first choice is nystatin in solution or lozenges, which acts locally on the mucosa without being absorbed systemically. It is the treatment of choice in mild to moderate cases, in pregnant women, and in babies.
When nystatin is not enough, when the infection is moderate or severe, or when significant immunosuppression exists, oral fluconazole is used, a systemic antifungal administered in a short 7-14 day course with cure rates over 90%. In cases of fluconazole resistance — more common in HIV patients — second-line antifungals such as itraconazole or voriconazole are used.
Rinses with bicarbonate water or 0.12% chlorhexidine are useful adjuncts to maintain hygiene and oral pH balance during treatment, but are not sufficient as monotherapy. It is essential to simultaneously treat the predisposing factor: adjust dentures, improve oral hygiene, correct hyperglycemia in diabetics, or review antibiotic treatment with the doctor. Without eliminating the cause, candidiasis recurs in 30-50% of cases.
How to prevent oral thrush?
Prevention of oral candidiasis is based on keeping risk factors under control. Denture wearers should remove them at night and clean them daily with specific antifungal solutions; an ill-fitting or micro-fissured prosthesis is a permanent reservoir for Candida that prevents healing. Patients using inhaled corticosteroids should always rinse their mouth with water after use to remove drug residue from the mucosa.
Controlling blood glucose in diabetic patients, maintaining correct oral hygiene, and regular check-ups with the dentist are the most effective preventive measures. This pathology falls within our oral medicine in Valencia specialty.
Frequently asked questions about oral candidiasis
Is oral thrush contagious?
Oral candidiasis has low contagious potential in healthy people, as Candida is part of the normal flora. However, it can be transmitted between babies and mothers during breastfeeding, and in immunocompromised people, the risk of contagion through direct contact is higher. If you have active oral candidiasis, avoid sharing utensils or close oral contact.
How long does it take to cure oral candidiasis?
With proper antifungal treatment, symptoms usually improve in 3-5 days and the infection resolves completely in 1-2 weeks. If symptoms persist for more than two weeks with treatment, it is necessary to review the diagnosis and predisposing factor, and consider a change of antifungal.
Can oral candidiasis be a sign of something serious?
In people without known risk factors, recurrent oral candidiasis or resistance to standard treatment can be a sign of an undiagnosed immunodeficiency, uncontrolled diabetes, or other systemic diseases. In these cases, it is important to perform a full medical evaluation in addition to dental treatment.
Can you have oral candidiasis without symptoms?
Yes. The erythematous form is especially silent and can go unnoticed for weeks. That’s why regular check-ups with your dentist are important: during oral examination, lesions that the patient has not yet noticed can be detected.