Oral Thrush (Candidiasis)

Candidiasis (Figure 1) is a common opportunistic oral mycotic (fungal) infection (opportunistic infection is an infection caused by bacterial, viral, fungal, or protozoan pathogens that take advantage of a host with a weakened immune system) that develops in the presence of one of several predisposing conditions. Clinical presentation is variable and is dependent on whether the condition is acute or chronic.

Its caused by Candida albicans and other candida species in oral flora which requires a predisposing factors along with opportunistic growth.

There are three main types of candidiasis, acute, chronic & mucocutaneous.

Figure 1: Oral Thrush.
Figure 1: Oral Thrush.


  • Candidiasis: Predisposing factors
  1. Immunodeficiency (Weak immune system)
  2. Immunologic immaturity of infancy
  3. Acquired immunosuppression (such as in HIV)
  4. Endocrine disturbances
  5. Diabetes mellitus
  6. Hypoparathyroidism (decrease release of hormones from the parathyroid gland, results in decreased calcium and phosphorus in the blood and may result in muscular spasms)
  7. Pregnancy
  8. Hypoadrenalism (decrease release of steroid hormones from the adrenal gland)
  9. Corticosteroid therapy, either topical or systemic (cortisol therapy)
  10. Systemic antibiotic therapy
  11. Malignancies and their therapies (such as chemotherapeutic treatment of cancer)
  12. Xerostomia (dry mouth)
  13. Poor oral hygiene

Infection with this organism is usually superficial, affecting the outer aspects of the involved oral mucosa or skin. In severely debilitated and immunocompromised patients, such as patients with AIDS, infection may extend into the alimentary tract (digestive tract), the bronchopulmonary tract, or other organ systems. The opportunistic nature of this organism is observed in the frequency of mild forms of the disease resulting from short-term use of systemic antibiotic therapy for minor bacterial infections.

  • Clinical Features

The most common clinical type of candidiasis is acute pseudomembranous form, also known as thrush. Young infants and elderly are commonly affected. This infection is common in patients being treated with radiation or chemotherapy for leukemia and solid tumors. Recalcitrant candidiasis has been recognized in patients who have HIV infection and AIDS.

  • Candidiasis: Classification


Pseudomembranous (white colonies)

Erythematous (red mucosa)


Erythematous (red mucosa)

Hyperplastic (white keratotic plaques)


Localized (oral, face, scalp, nails)


Syndrome associated

Oral lesions of acute candidiasis (thrush) are characteristically white, soft plaques that sometimes grow centrifugally and merge (Figure 2 – 8).

Figure 2: Candidiasis, pseudomembranous type.
Figure 2: Candidiasis, pseudomembranous type.
Figure 3: Candidiasis, pseudomembranous type.
Figure 3: Candidiasis, pseudomembranous type.
Figure 4: Candidiasis, pseudomembranous type.
Figure 4: Candidiasis, pseudomembranous type.
Figure 5: Candidiasis, erythematous type.
Figure 5: Candidiasis, erythematous type.
Figure 6: Candidiasis, angular cheilities form.
Figure 6: Candidiasis, angular cheilities form.
Figure 7: Candidiasis, hyperplastic type or median rhomboid glossitis.
Figure 7: Candidiasis, hyperplastic type or median rhomboid glossitis.
Figure 8: Candidiasis, hyperplastic type.
Figure 8: Candidiasis, hyperplastic type.

Plaques are composed of fungal organisms, keratotic debris, inflammatory cells, desquamated epithelial cells, bacteria, and fibrin. Wiping away the plaques or pseudomembranous with gauze sponge leaves a painful erythematous, eroded, or ulcerated surface. Although lesions of thrush may develop at any location, favored sites include the buccal mucosa and mucobuccal fold, the oropharynx, and the lateral aspects of the tongue. In most instances in which the pseudomembrane has not been disturbed, associated symptoms are minimal. In severe cases, patients may complain of tenderness, burning, and dysphagia (difficulty or discomfort in swallowing).

Persistence of acute pseudomembranous candidiasis may eventually result in loss of the pseudomembrane, with presensation as a more generalized red lesion, known as acute erythematous candidiasis. Along the dorsum of the tongue, patches of depapillation and dekeratinization may be noted. In contrast to the acute pseudomembranous form, oral symptoms of the acute atrophic form are marked because of numerous erosions and intense inflammation.

Chronic erythematous candidiasis is a commonly seen form, occurring in as many as 65% of geriatric individuals who wear complete maxillary (upper jaw) dentures. Expression of this form of candidiasis depends on conditioning of the oral mucosa by a covering prosthesis. A distinct predilection for the palatal (roof of the mouth) mucosa as compared with the mandibular alveolar arch (lower jaw arch) has been noted. Chronic low-grade trauma resulting from poor prosthesis fit, less than ideal occlusal relationships, and failure to remove the appliance at night all contribute to the development of this condition. The clinical appearance is that of a bright red, somewhat velvety to pebbly surface, with relatively little keratinization (white surfaces).

Also seen in individuals with denture-related chronic atrophic candidiasis is angular cheilitis. This condition is especially prevalent in individuals who have deep folds at the commissures (angle of the mouth) as a result of mandibular (lower jaw) overclosure. In such circumstances, small accumulations of saliva gather in the skin folds at the commissural angles and are subsequently colonized by yeast organisms. Clinically, the lesions are moderately painful, fissured, eroded, and encrusted. Angular cheilitis may also occur in individuals who habitually lick their lips and deposit small amounts of saliva in the commissural angles.

A circumoral type of atrophic candidiasis may be noted in those with severe lip-licking habits with extension of the process onto surrounding skin. The skin is fissured and demonstrates a degree of brown discoloration on a slightly erythematous base. This condition is to be distinguished from perioral dermatitis (is skin disease characterised by multiple small papules, pustules and vesicles which are localized to the perioral skin-around the mouth-.), which characteristically shows less crusting and circumferential zone of uninvolved skin immediately adjacent to the cutaneous-vermilion junction.

Chronic candidal infections are capable of producing hyperplastic tissue response (chronic hyperplastic candidiasis). When occurring in the retrocommissural area, the lesion resembles speckled leukplakia and, in some classifications, is known as candidial leukoplakia. It occurs in adults with no apparent predisposition to infection by C.albicans, and it is believed by some clinicians to represent a premalignant lesion.

Hyperplastic candidiasis may involve the dorsum of the tongue in a pattern referred to as median rhomboid glossitis. It is usually asymptomatic and is generally discovered on routine oral examination. The lesion is found anterior to the circumvallate papilla (type of papilla present medially at the posterior third of the tongue) and has an oval or rhomboid outline with a paramedian distribution. It may have a smooth, nodular, or fissured surface and may range in color from white to a more characteristic red. A similar-appearing red lesion may also be present on the adjacent hard palate (roof of the mouth) “kissing lesion”. Whether on the tongue or on the palate, the condition may occasionally be mildly painful, although most cases are asymptomatic.

Nodular papillary lesions of the hard palate (roof of the mouth) mucosa predominantly seen beneath maxillary (upper jaw) complete dentures are thought to represent, at least in part, a response to chronic fungus infection. The papillary hyperplasia is composed of individual nodules that are ovoid to spherical and form excrescences measure 2 to 3 mm in diameter on an erythematous background.

Mucocutaneous Candidiasis is a diverse group of conditions. The localized form of mucocutaneous candidiasis is characterized by long-standing and persistent candidiasis of the oral mucosa, nails, skin, and vaginal mucosa. This form of candidiasis is often resistant to treatment, with only temporary remission following the use of standard antifungal therapy. This form begins early in life, usually within the first two decades. The disease begins as a pseudomembranous type of candidiasis and soon is followed by nail and cutaneous involvement.

A familial form of mucocutaneous candidiasis, believed to be transmitted in an autosomal-recessive fashion (two copies of an abnormal gene must be present in order for the disease or trait to develop), occurs in nearly 50% of patients with an associated endocrinopathy. The endocrinopathy usually consists of hypoparathyroidism, Addison’s disease, and occasionally hypothyroidism or diabetes mellitus. Other forms of familial mucocutaneous candidiasis have associated defects in iron metabolism and cell-mediated immunity.

A rare triad of chronic mucocutaneous (a region of the body in which mucosa transitions to skin) candidiasis, myositis (inflammation and degeneration of muscle tissue) , and thymoma (a tumor originating from the epithelial cells of the thymus) has been described. The role of thymus relates to deficiency in T cell-mediated immunologic function, hence providing an opportunity for the proliferation of Candida. 

A final form of candidiasis, both acute and chronic, is becoming increasingly evident within the immunosuppressed population of patients, in particular those infected with HIV. This form of candidiasis was originally described in 1981 and is now well recognized as being one of the more important opportunistic infection that afflict this group of patients. This significantly depleted cell-mediated arm of the immune system is believed to be responsible for allowing the development of severe candidiasis in these patients.

So-called denture stomatitis, a chronic form of erythematous candidiasis, is in large measure associated with the prosthesis-related surface biofilm (a thin, slimy film of fungi that adheres to a surface) that becomes colonized with candidal organisms.

  • Differential Diagnosis

Candidal white lesion should be differentiated from slough associated with chemical burns, traumatic ulcerations, mucous patches of syphilis, and white keratotic lesions. Red lesions of candidiasis should be differentiated from drug reactions, erosive lichen planus, and DLE (discoid lupus erythematosus).

  • Treatment & Prognosis

Attending to predisposing factors is an important component of management of patients with candidiasis. The majority of infections may be treated simply with topical applications of nystatin suspensions, although this may be prove to be ineffective because contact time with the lesion is short. Nystatin powder, cream, or ointment is often effective when applied directly to the affected tissue on gauze pads and for denture-associated candidiasis when applied directly to the denture bearing surface itself. In both circumstances, prolonged contact time with the lesion proves to be an effective delivery strategy. Clotrimazole can be conveniently administered in troche form. Topical applications of nystatin miconazole or clotrimazole should be continued for at least 1 week beyond the disappearance of clinical manifestations of the disease. It is important to note that antifungals designed specifically for oral use contain considerable amounts of sugar, making them undesirable for the treatment of candidiasis in dentulous patients with xerostomia. Sugar-free antifungal vaginal suppositories, dissolved in the mouth, are an excellent treatment alternative to avoid the complications of dental caries.

For hyperplastic candidiasis,topical and systemic antifungal therapy may be ineffective in completely removing the lesions, particularly those that occur in the buccal mucosa, near the commissures. In these circumstances, surgical management may be necessary to complement antifungal medications.

In cases of chronic mucocutaneous candidiasis or oral candidiasis associated with immunosuppression, topical agents may not be effective. In such instances, systemic administration of medications such as ketoconazole, fluconazole, itraconazole, or others may be necessary. All are available in the oral form. Caution must be exercised, however, because those drugs may be hepatotoxic.

The prognosis for acute and most other forms of chronic candidiasis is excellent. The underlying defect in most types of persistent mucocutaneous candidiasis militates against cure, although intermittent improvement may be noted after the use of systemic antifungal agents.

Candidiasis: Treatment

  • Topical

Nystatin – oral suspension* and pastille*; powder and ointment for denture; vaginal tablets (dissolved in mouth)

Clotrimazole – oral trouches*

  • Systemic

Fluconazole, ketoconazole

*Contains sugar; do not use with dentate patients with xerostomia.

Reference: Oral Pathology, Sixth Edition, By Regezi, Sciubba, & Jordan.

Now i want to hear from you!

Have you ever suffered from candidiasis? & what did you do to treat it?

I read each & every comment.

Haider Maitham, DDS


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