5.5 Fungal (mycotic) infections

5.5.1 Oral candidosis (formerly moniliasis, thrush)

This inflammatory disease is caused by yeasts with predilection to the oral cavity from where it can further spread into the mucosa of the pharynx, esophagus or even respiratory pathways. The responsible yeasts are most commonly of the Candida genus (C. albicans, C. glabrata, C. tropicalis), i.e., saprophytic organisms normally present in the oral cavity (in our population, these species can be found in 40-50 % of healthy individuals).

The proliferation of these occurs in predisposed individuals following a local or systemic disruption of the immune system. Multiple predilection factors can lead to the development of the disease (physiological – pregnancy; patophysiological – trauma, chemical trauma to the mucosa; serious infections; endocrine disruptions such as diabetes, malabsorption; haematological diseases such as leukaemia, agranulocytosis, aplastic anaemia; some medications such as immunosuppresants, corticoids, cytostatics or broad-spectrum antibiotics that can suppress many physiological microorganisms and thus aid the development of the yeast infection).

An important role in the disease development is attributed to certain properties of the yeasts, particularly to their capability to stick to the surface of the oral mucosa (and to the surface of plastics including dental prosthetic devices) and to grow through the epithelial wall of the oral mucosa, which in turn leads to a change in the character from saprophytic to the parasitic. The combined action of multiple local or general factors, the number of which increases due to the modern way of life, highly increases the susceptibility to this affliction and the number of individuals at risk of this disease therefore keeps increasing.

Clinical picture can be varied. The “white” (pseudomembranous and hyperplastic) and a “red” (erythematous) form without coating represent the most typical forms.

Dg.: Diagnosis of both pseudomembranous and erythematous forms of candidosis is based on the clinical appearance, mycological examination (microscopy, cultivation) and, if need be, histopathological, serological and/or immunological proof of the presence of yeasts. The patient’s history is also important for differentiation (systemic diseases, recent ATB treatment, immunosuppressants).

Th.: Where possible, antimycotic therapy (both local and systemic) should be combined with the treatment of the predisposing illnesses. The therapy must be driven by the severity of problems, patient’s health condition and, if applicable, sensitivity of the yeasts to the applied antimycotic therapy. Local treatment is always sufficient in angular candidosis and mostly in acute candidosis. In chronic forms of the disease, however, a complex antimycotic therapy (ideally using the 3rd generation of azol antimycotics, so-called triazoles) should augment the local therapy. One must however bear in mind the relatively large number of potential drug interactions and risk of liver damage due to the long-term usage of triazoles.

In atrophic candidosis (see below), the optimum solution lies in constructing a new denture (or a laboratory rebase) and maintaining a proper hygiene of the denture (i.e., mechanical cleaning every day after food, washing with soap/disinfectant and brush under running water every evening, and submerging the denture into a cleaning antibacterial solution overnight; such a cleaning solution is to be prepared by dissolving special cleaning tablets in the water). Supplementary measures may include general introduction of good hygiene to the oral cavity, management of carious teeth, treatment of the periodontium and extraction of destructed teeth and radices (elimination of the yeast reservoirs). The treatment of predisposing illnesses, if possible, is important, as is smoking cessation or at least reduction. The therapy should not be interrupted before a full regression of the clinical manifestations and/or negative mycological examination. In patients with a systemic disease predisposing to the development of oral candidosis, a long-term prophylaxis (general or local) is recommended.

Dif. dg.: It is necessary to distinguish this disease from other mucosal diseases with keratinization disorders in the sense of hyperkeratosis and parakeratosis that also lead to the development of „white areas“.

Acute pseudomembranous candidosis


This is the most common, typical form of candidosis with sudden onset and formation of whitish partially removable coatings (pseudomembranes) resembling curdled milk – colonies of yeasts. These pseudomembranes have no predilection for a particular location in the oral cavity, it is however uncommon for them to occur on the gingiva. Due to the pseudohyphae penetrating the surface layers of the mucosal epithelium, the coating is firmly attached to the mucosa and if forcibly removed, the mucosa bleeds or erosions appear. In the surroundings of the coatings, the mucosa is markedly erythematous. Subjective complaints may range from burning or increased sensitivity to painfulness of the affected mucosa and disorders of taste perception. Painful swallowing should lead us to suspect the spreading of the infection into the GIT. If the inflammation does not heal spontaneously or after therapy, it can turn into a chronic disease, to the process dissemination or generalization of the process.

Acute erythematous candidosis

The disease typically develops as a result of dysmicrobia in the oral cavity or the entire GIT, mostly due to treatment with broad-spectrum ATBs. Clinically, it manifests only through a formation of diffuse erythema on the mucosa (without pseudomembranes) associated with pain, burning and sensation of dryness in the mouth. Corners of the mouth can be inflamed as well. If correct therapy is administered and the intestinal microflora restored, the disease regression is quick.

Chronic pseudomembranous candidosis


This disease represents a serious affliction of the oral mucosa, bearing a risk of dissemination and generalization of the process. It especially affects immunodeficient or oncological patients. The candidosis is usually extensive and progresses into the oropharynx and other parts of the gastrointestinal and respiratory tracts. The patient often only complains about problems swallowing. Spontaneous regression of the disease is rare; the success of the therapy however depends on the overall condition of the patient and effectiveness of the antimycotic therapy.

Chronic hyperplastic candidosis


This form of oral candidosis is relatively rare. The affliction is always a long-term one (months to years). It can appear as a part of so-called chronic mucocutaneous candidosis, especially in individuals with congenital immunological disorders. It first manifests in childhood and is frequently associated with certain endocrine disorders such as a hypofunction of adrenal medulla and parathyroid glands or myastenia. Subjective complaints are usually minimal, sometimes even absent, which is however in a direct contrast to the extent of the defect (white non-removable lesions, most commonly on the buccal mucosa and tongue, the immediate vicinity of which is normal, without any erythema. The treatment is very difficult.

Chronic erythematous atrophic candidosis


Most commonly, this disease develops as a so-called „prosthetic stomatitis“ in patients with removable dentures. It particularly affects the mucosa of the denture bed, where either massive induration and papillomatous, hypertrophic mucosa or, contrary, erythematous atrophic surface can be found. This form has a high tendency to recur – most likely, such recurrences are repeated reinfections as the prosthesis serves as a yeast reservoir. Making a new denture and a meticulous hygienic care for it is an optimal solution for preventing the oral candidosis. The mucosa of the dorsum of the tongue is another common site of the chronic atrophic candidosis. Here, it is without pseudomembranes, markedly erythematous, sometimes with papillomatous hypertrophy and normal surroundings of the lesion.

Angular candidosis


This disease (usually caused by C. albicans) affects the skin and mucosa solely of the corners of mouth but can also be associated with more extensive lesions of the oral cavity. Typical appearance includes crevices and erythematous patches with indistinct whitish margins of the labial mucosa, often bilaterally. Deeper defects such as fissures, bleeding or formation of suppurative discharges and crusts are uncommon. In patients suffering with this disease, we often observe a reduced height of bite due to defective dentition with unsuitable dentures. The corners of the mouth become macerated with saliva, which leads to further aggravation of the complaints. In children, a secondary streptococcal infection (impetigo) can develop and spread further on the surrounding facial skin.

Dg.: Of the examination methods, bacteriological and mycological examinations are the most important; where the disease persists, haematological and biochemical examinations (glycaemia) should be employed, along with sialometry and assessment of the quality of the dentures. The presence of Staphylococcus aureus is often detected during such examinations.

Th.: Firstly, removal of the provoking cause should be attempted (reconstruction of the height of bite – rebase, new denture, replacement of the supporting zones). The treatment varies according to the etiology. Antimycotics (nystatin, azole antimycotics), should be administered; if bacterial infection is proved, local ATBs should be also used (neomycin). In adult patients, combined preparations containing anti-inflammatory corticosteroids may be applied (the application of those however must be well thought through and remain short-term!).

Dif. dg.: Herpes simplex (labialis) in the area of the corners of mouth is usually one-sided, the eruption is preceded by prodromes (paresthesia), the vicinity of the lesion is usually erythematous and oedematous, sometimes painful. The syphilitic primary chancre is one-sided, painless erosion or crevice with hard bottom; painless swelling of lymphatic nodes is also common. Another disease that can be mistaken for angular candidosis is a squamous cell (or, less commonly, other) carcinoma of the lip, which is usually painless, irresponsive to treatment and usually is larger (hence, if the lesion does not respond to therapy within 1-2 weeks, a surgical excision at a specialized department is necessary!).

Median rhomboid glossitis (glossitis rhombica mediana, Brocque-Pautrier’s glossitis)


This glossitis manifests as an erythematous smooth oval, rectangular or diamond-shaped patch on the mucosa in the central third of the dorsum of the tongue (in front of the circumvalate papillae). The surface is markedly smooth, glossy and red, the physiological surface formed by the filiform and fungiform papillae is missing in the lesion. In some cases, however, bumps may occur on the surface, which can lead to cancerophobia in the patient. The mucosa can be more sensitive or even painful, especially during tactile perception or speech. The disease only affects adults, the etiology is not completely clear. In the past, the condition was considered congenital (rest of the median tongue bud). At present, it is, due to the typical coincidence with yeast infection, classified as a candida-associated lesion. The smear cultivation usually proves the presence of yeasts.

Th: Therapy is difficult – elimination of smoking and mechanical irritation, antimycotic therapy (particularly local antimycotics but if need be, systemic administration is possible).

Dg.: In differential diagnosis, simple mechanical irritation of the dorsum of the tongue, geographic tongue, acute erythematous candidosis, herpetic glossitis and haemangioma must be considered.

Black hairy tongue (lingua villosa nigra)


Hyperplasia and hyperkeratosis of the filiform papillae with the appearance as if combed down towards the tip of the tongue are typical of this disease. The hyperplasia is most prominent around the median sulcus in the distal and central thirds of the dorsum of the tongue. The discoloration can be caused by chromogenic bacteria, smoking, poor oral hygiene, use of broad spectrum antibiotics or some oral antiseptics such as chlorhexidine (CHX) or hydrogen peroxide, in particular when using them for longer periods of time and/or at increased concentrations. Due to its coexistence with yeast infection, this affliction of the tongue is currently counted among candida-associated lesions. It is therefore associated with dysmicrobia in GIT or just the oral cavity followed by the proliferation of the yeasts. Over the course of several days, a massive yellow to blackish-brown coating of the central third of the tongue develops as a result of hyperkeratosis, hypertrophy and hyperpigmentation of filiform papillae. The patients usually do not suffer with any subjective complaints. The disease mostly affects adults, only rarely children.

Th.: Local antimycotic treatment combined with mechanical removal of the coating using large spoon excavators, toothbrushes (or using swabs, which can however be unpleasant or even painful). Systemic administration of nicotinamide is also possible (when its deficiency due to the disruption of its synthesis by GIT microorganisms is suspected), elimination of smoking is also beneficial.

Dif. dg.: acanthosis nigricans „maligna“

5.5.2 Systemic (deeply invasive) mycoses


These invasive opportunistic fungal infections (aspergillosis, zygomycosis, cryptococosis, histoplazmosis) affect mostly seriously immunosuppressed individuals. The invasion of such microorganisms into the vascular bed and the subsequent formation of thrombi leads to a necrosis of the surrounding tissues.

Clinical picture: Non-healing ulcers and necroses affecting in particular the hard palate and alveolar process of the upper jaw. The disease progresses rapidly, spreading into the entire organism and often leading to death of the patient.

Th.: Therapy is very difficult, it includes intravenous antimycotics and surgical removal of necroses and ulcers.