Oral candidiasis

Introduction:

Oral candidiasis is a very common fungal infection involving the oral cavity mucosa. These infections are caused by saprophytic fungi belonging to the genus candida.

Common organisms involved in oral candidiasis include:

Candida albicans

Candida glabrata

Candida tropicalis

Among these organism candida albicans has been implicated as the common causative organism in oral candidiasis. Candida albicans is dimorphic in nature, capable of existing in two forms i.e yeast and hyphal forms. The hyphal form is associated with oral candidiasis. Studies have shown that candida albicans can exist in the oral cavity as normal commensal.

Predisposing factors causing oral candidiasis:

1. Poorly controlled diabetes mellitus

2. In HIV positive patients with CD 4 count less than 200/microlitre

3. Patients with xerostomia – Use of medications in the elderly are the common cause of xerostomia. Medications known to cause xerostomia include: antidepressants, diuretics and drugs with anticholinergic effects.

4. Use of broad spectrum antibiotics that could alter the normal gut flora.

5. Use of systemic steroids

Clincially oral candidiasis can present as both erythematous / white forms. White forms are otherwise known as pseudomembranous type / hyperplastic candidiasis.

Types of oral candidiasis:

Pseudomembranous candidiasis: This is the commonly seen type of oral candidiasis. It is also known as oral thrush. It is usually seen as whitish patches resembling curd over the oral cavity mucosa. When these white plaques are peeled off it will expose the underlying erythematous mucosa. This type of oral candidiasis is common in:

Infants Immunocompromised patients (even patients with HIV) Patients who have undergone organ transplant surgeries and are on antirejection drugs

Erythematous candidiasis: Oral cavity mucosa in these patients appear erythematous. This type of candidiasis is commonly seen in patients with xerostomia and in those who wear prosthetic appliances for long periods of time. Subtypes of erythematous candidiasis include:

Acute atrophic candidiasis – This type of oral candidiasis is also known as antibiotic sore mouth, since it is common in patients taking broad spectrum antibiotics which could alter the normal gut flora. These patients typically manifest with erythema of the affected area of oral mucosa with atrophy of dorsal lingual papillae. The major problem faced by these patients is excessive burning sensation in the affected area. This type of candidiasis is seen in patients with iron deficiency anaemia, vitamin B12 deficiency etc. Some patients sould be long standing diabetics.

Chronic atrophic candidiasis – This is also known as denture stomatitis. This type of candidiasis is commonly seen in patients wearing ill fitting dentures for prolonged duration, as well as in those who dont remove their dentures even during night time. These patients usually present with erythema of mucosa overlying the denture area. This type of oral candidiasis is common in the palatal region of denture area which is poorly drenched by saliva.

Newton classified denture stomatitis into three clinical types:

Type I – This is characterized by localized inflammation associated with pin point hemorrhages.

Type II – In this type there is more diffuse erythema involving either a portion / entire denture bearing area.

Type III – There is erythema of the denture bearing mucosa with papillary hyperplasia. Fungal cultures from the mucosal surface of denture / from palatal area covered by denture always reveal candida albicans. The pores over the acrylic surface of dentures provide perfect environment for growth of candida albicans.

Angular chelitis:

This condition is caused by a combination of candida albicans and bacterial infection. This condition is caused by candida albicans i and staphylococcal aureus mixed infections. These patients have fissures / sores along the angle of the mouth. This condition usually involves both angles of mouth. This condition is commonly seen in patients using ill fitting dentures. Ill fitting dentures cause recession of alveolar margins causing a decrease in the vertical dimension of occlusion leading on to accumulation of saliva at the angle of the mouth. This prolonged stasis of saliva at the angle of the mouth causes a favourable environment for growth of candida albicans.

Other conditions causing angular chelitis include nutritional deficiencies like:

Iron

Folic acid

Vitamin B 12

Thiamine

Riboflavin

Median rhomboid glossitis:

This condition goes by another name i.e. Central papillary atrophy. These patients manifest with well demarcated area of atrophy of the dorsal lingual papillae. This area appears like a rhomboid. This lesion lies just anterior to the circumvallate papillae of the tongue. Some of these patients may have associated lesion over the corresponding portion of the palatal mucosa where the posterior portion of tongue comes into contact during oral phase of deglutition. These are known as satellite / kissing lesions.

Chronic multifocal candidiasis:

This condition is characterised by candidal infection in more than one location. These patients may have concurrent denture stomatitis along with angular stomatitis.

Hyperplastic candidiasis:

This condition also goes by the name candida leukoplakia. Lesions in these patients are whitish and well defined covering large areas of oral mucosa. These whitish patches cannot be peeled off from the mucosa. These lesions are commonly seen in the buccal mucosa, palate, and tongue areas. It is nearly impossible to distinguish this lesion clinically from leukoplakia. Diagnosis is usually made in retrospect if the patient doent respond to topical antifungal agents. Ofcourse these patients dont give history of tobacco use.

Chronic mucocutaneous candidiasis:

These patients have long term involvement of mucosa of oral cavity, skin and nails of hand. This condition is resistant to topical antifungal agents.

These patients also have associated endocrine abnormalities like:

Hypothyroidism

Addison's disease

Diabetes mellitus

Diagnosis:

Classically diagnosis of oral candidiosis depends on clinical signs and symptoms.

Other diagnostic adjuncts include:

Exfoliative cytology: Samples can be obtained from scrappings of wooden tongue blade. The sample is then smeared on to a glass slide. It can be fixed with alcohol fixative / allowed to air dry. The slide is then stained with PAS which shows up the fungal hyphae.

Biopsy

Fungal culture

Qualitative assessment of candida albicans:

This gives an approximate estimate of the probablity of candida infection. This test is performed by determining the number of colony forming units of candida albicans present in 1 ml of unstimulated saliva. The number of colony forming units can be determined after 72 hours of incubation at 30 degrees centigrade in the saburaud agar plate. In healthy individuals the count usually is zero.

Management:

1. Improving the hydration levels of the patient

2. Treating immune deficiency status

3. Correction of nutritional deficiencies

4. Antifungal agents - These agents act by altering DNA / RNA metabolism. They could also allow intracellular accumulation of peroxide which could prove toxic to the fungal cell.

Topical antifungal agent:

Clotrimazole lozenges: This is administered as 10 mg losenges to be dissolved in the oral cavity five times a day for two weeks. It also has a certain degree of anti staphylococcal activity.

Miconazole buccal tablet: 50 mg tablet to be dissolved in the oral cavity each morning for 2 weeks.

Genitian violet solution: useful in managing refractory and highly localised lesions.

Ketaconazole cream

Systemic antifuncal agents:

Cap. Fluconazole – 50 – 100 mg qid

T. Ketoconazole – 200 – 400 mg qid

T. Miconazole – 50 mg qid

T. Itraconazole – 100 mg qid