Oral candidiasis is an infection of the oral cavity by Candida albicans. It was first described in 1838 by the pediatrician Francois Veilleux.
Oral candidiasis usually occurs secondary to immune suppression , whether the patient’s oral cavity has decreased immune function or is systemic. This immunosuppression is dose dependent.
Examples of systemic immunosuppression are very young or very old age, immunocompromising conditions such as HIV/AIDS, and chronic use of systemic steroids/antibiotics. An example of local immunosuppression is inhaled corticosteroids (often in the preventive treatment of asthma and chronic obstructive pulmonary disease).
For this reason, patients using such medications are instructed to rinse their mouth with water after each use. Oral thrush is transmitted through kissing and breastfeeding.
Etiology
Oral candidiasis is caused by the Candida species, most commonly Candida albicans . It can also result from Candida glabrata, Candida tropicalis and Candida krusei . Non-albicans Candida species have been shown to colonize patients aged 80 years or older more frequently than younger patients.
Epidemiology
Oral candidiasis can occur in immunocompetent or immunocompromised patients, but is more common in immunocompromised hosts. It occurs equally in men and women.
It usually occurs in newborns and infants. It is rare for patients to have it in the first week of life. It is most common during the fourth week of life and less common in infants older than 6 months (probably secondary to the development of host immunity). Signs and symptoms of immunosuppression in these patients include diarrhea, rashes, repeated infections, and hepatosplenomegaly.
Pathophysiology
Candidate species cause oral candidiasis when the patient’s host immunity is disrupted. This alteration may be local, secondary to the use of oral corticosteroids.
Excessive growth of the fungus leads to the formation of pseudomembranes.
Vaginal Candida infections can colonize newborns as they pass through the birth canal. Alternatively, newborns and infants can contract the disease through breasts colonized during breastfeeding.
Often, a patient’s oral Candida infection can lead to gastrointestinal involvement and subsequent Candida diaper rash. Candida species thrive in moist environments. As such, women can also develop vaginal yeast infection.
In healthy patients , the patient’s immune system and normal bacterial flora inhibit the growth of candida. Consequently, immunosuppression in forms such as diabetes, smoking, dentures, steroid use, malnutrition, vitamin deficiencies, and recent antibiotic use often lead to the disease.
Histopathology
Plates can be cultured, Gram stained, and potassium hydroxide stained. Gram stain shows large, ovoid, gram-positive yeasts. Potassium hydroxide staining shows pseudohyphae.
Clinical History and Physical Examination
Patients generally present with the complaint of patchy white lesions on the tongue and/or buccal mucosa. There is often an associated history of immunosuppression, such as smoking, use of antibiotics and/or steroids, immunosuppressive medications in transplant patients, use of dental prostheses, malnutrition, etc.
Clinically, oral candidiasis consists of white pseudomembranous plaques. They are difficult to remove and affect the oral mucosa, tongue and both hard and soft palates. It is usually painless, associated with loss of taste and angular cheilitis (cracking of the skin in the corner of the patient’s mouth). The plaques are often difficult to scrape off with a tongue depressor. After scraping, there are often swollen, painful lesions that may bleed.
Patients may also have a Candida rash in other regions of their bodies. For example, newborns can have diaper rash and, in adults, it can spread to the esophagus and cause esophagitis presenting with odynophagia or to the larynx, causing hoarseness.
Assessment
The diagnosis of oral candidiasis is often clinical, based on appearance and risk factors. Furthermore, the appearance of an erythematous, swollen and bleeding base after scraping the plaques also leads to a probable diagnosis of oral candidiasis.
For further confirmation, the plates can be cultured.
Alternatively, a Gram stain of plaques showing large, ovoid, gram-positive yeasts is diagnostic. Finally, pseudohyphae can be seen with a potassium hydroxide stain.
In addition to confirmation of candidiasis, it is important to perform tests to diagnose an underlying immunocompromising condition. Patients should be interviewed, examined, and evaluated accordingly for diseases such as HIV, adrenal insufficiency, malnutrition, steroid use, and diabetes.
Treatment
Treatment focuses on Candida species. It should be directed to the extent of the involvement and degree of immunosuppression of the patient. In general, antifungal agents are the recommended treatment. These treat the infection by altering RNA or DNA metabolism or by causing intracellular accumulation of peroxide in fungal cells.
For patients with a mild presentation or first presentation of the disease, topical treatment is recommended . One option is clotrimazole swabs 10 mg orally five times a day (dissolved in 20 minutes).
Another is nystatin oral suspension (100,000 units/ml), 5 ml orally four times a day (shaken for several minutes and then swallowed). In appropriate circumstances, miconazole oral gel may also be an option.
For moderate to severe disease, fluconazole 200 mg orally once and then 100 mg orally once daily for a total of 7 to 14 days is recommended. Data on the safety of fluconazole during breast-feeding are reassuring.
For refractory disease , options are itraconazole oral solution 200 mg once daily without food for 28 days, posaconazole suspension 400 mg orally twice daily for 3 days, then 400 mg orally daily for a total of 28 days and voriconazole 200 mg orally twice daily for 28 days.
Additionally, the single oral dose of fluconazole 150 mg has been shown to be effective in patients with advanced cancer, helping to reduce pill burden.
For vaginal yeast infection, several over-the-counter options are available: clotrimazole cream 1% vaginally for 7 to 14 nights, clotrimazole cream 2% vaginally for 3 nights, miconazole cream 2% vaginally for 7 nights, 4% miconazole cream vaginally for 3 nights, 100 mg miconazole suppository vaginally for 3 nights, 6.5% tioconazole ointment vaginally once.
There are also prescribed therapies: vaginal tablet of 100,000 units of nystatin for 14 nights, terconazole 80 mg one suppository vaginally for 3 nights, terconazole cream 0.8% vaginally for 3 nights, butoconazole cream 2% one applicator vaginally once (do not use during the first trimester of pregnancy).
Lastly, an oral therapy option is fluconazole 150 mg PO once (may repeat in 72 hours if symptoms persist).
Oral azoles are teratogenic and should not be used to treat mucosal candidiasis during the first trimester. Clotrimazole troches, topical nystatin rinse and swallow therapies, and miconazole buccal tablets are also a treatment option.
The dosage of these regimens should be adjusted according to the weight of pediatric patients.
In addition to treatment, patients should be counseled on decreasing immunosuppressive conditions, such as uncontrolled diabetes, smoking, and malnutrition.
Differential diagnoses
If the diagnosis of oral candidiasis is suspected in a patient with oral lesions, the differential diagnosis of oral hairy leukoplakia (condition triggered by the Ebstein-Barr virus), angioedema, aphthous stomatitis, herpes gingivostomatitis, cold sores, measles should be performed. (Koplik spots), perioral dermatitis, Steven-Johnson syndrome, histiocytosis, blastomycosis, lymphohistiocytosis, diphtheria, esophagitis, syphilis and streptococcal pharyngitis among other conditions should be considered.
Forecast
The prognosis of a patient with oral candidiasis often depends on his or her degree of immunosuppression. Those who are immunocompetent will often achieve resolution of disease and symptoms. Those who are immunocompromised often need concomitant treatment of their immunosuppressive condition to fully recover.
Complications
Although unlikely in an immunocompetent host, oral candidiasis can cause pharyngeal involvement . Symptomatically, this can cause dysphagia and respiratory distress. A major concern for immunocompromised patients is systemic dissemination of the disease.
Candida esophagitis is a particularly common complication of oral candidiasis in people with HIV/AIDS.
Patient education
Patients with oral candidiasis should be counseled about the future spread of the disease. They also need to understand the importance of diagnosing and treating any immunosuppressive conditions. It can also appear in immunocompetent patients who wear dental prostheses or have been taking steroids for a long time.
Aspects to consider
One of the most critical educational pearls regarding the diagnosis and treatment of Candida candidiasis is clinical suspicion . A healthcare provider should take a complete history to know when a patient has an immunocompromising condition. Knowing this may lead the healthcare provider to evaluate for candidiasis first and be aware of the possibility of other life-threatening systemic infections.
Improving healthcare team outcomes
Oral candidiasis is a diagnosis that is important to make. Patients usually have white and/or gray spots on the oral mucosa. They may also have systemic manifestations of their immunocompromised state. Examples of these are dysphagia secondary to pharyngeal candidiasis, growth retardation, and sepsis. Case management for most of these patients will be handled by the primary care provider, nurse practitioner, and obstetrician.
Since the diagnosis and treatment of oral candidiasis has several important implications for the patient, healthcare professionals must work together as an interprofessional team.
Registered nurses , physician assistants, nurse practitioners, and physicians must collaborate in the areas of triage and diagnosis to correctly diagnose oral thrush. Pathologists may be involved to evaluate the culture and stain oral scrapings. Depending on the underlying immunosuppressive condition, oncologists and infectious disease specialists may provide consultations.
Since oral candidiasis is often the first sign of a significant systemic immunocompromising condition, it is very important that the primary health care provider transition the patient to specialists who will continue to monitor their chronic disease.
The pharmacist should educate the patient about the importance of medication adherence, verifying medication dosage and checking for drug interactions, and reporting any concerns to the healthcare team.
Patients with diabetes should be urged to control their blood sugar levels. Additionally, the patient should be instructed to stop smoking. Patients taking inhaled steroids should be asked to gargle with water after each use and follow up with their doctor.
Lastly, it is imperative that healthcare providers treating people susceptible to oral candidiasis are aware of the usefulness of preventive strategies. For example, through randomized controlled trials, probiotics, for example, have been shown to prevent oral thrush in the elderly.
