What Is Mycology and Mycotic Infections?
The study of fungal infections is known as mycology. Mycotic infections occur in humans due to immune impairment leading to the initiation and progression of pathogenic conditions. Some fungal (also called mycotic) infections are life-threatening when left untreated. Furthermore, when they affect multiorgan systems, it can lead to grave consequences. In many mycotic infections, patients suffer from oral manifestations.
What Are the Various Mycotic Infections Affecting Oral Cavity?
In the oral cavity,superficial mycotic infections present with discomfort, pain, burning sensation, altered taste, and food aversions. On the contrary, deep fungal infections occur through the dissemination of pathogens to deeper tissue areas. Further, they have aggressive clinical presentations such as deep ulcerations and bony perforations. The fungal diseases and their oral manifestations are described below.
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Candidiasis: It is a very prevalent oral mycotic infection and is frequently encountered by the dental surgeon. Candidiasis is caused by Candida albicans fungus that primarily infects human beings in three forms: pseudohyphae, yeast, or chlamydospore. It may be surprising to know that Candida albicans is a normal commensal of the oral microbiome. However, the predisposing risk factors for candidiasis are chronic illnesses, immune deficiencies, and systemic diseases. Oral lesions of this fungal infection commonly occur on the tongue and buccal (cheek) mucosa at any age. However, candidiasis has a predilection for infants and immunocompromised individuals. While pseudomembranous candidiasis (also called oral thrush) is the most commonly observed infection, secondary Candida lesions or Candida-associated lesions are also common in individuals with poor oral immunity, poor oral hygiene, and immunocompromised status.
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North American Blastomycosis: It is also called Gilchrist disease. North American Blastomycosis is a mycotic infection caused by the fungus Blastomyces dermatitidis and has skin manifestations. The disease spreads to bones, liver, and lungs with numerous oral manifestations. The symptoms are fever, weight loss, and cough, with typical symptoms similar to pulmonary (lung) tuberculosis. Oral lesions present as ulcers in the oral cavity. They may be the primary lesions or a result of lesions in the body. About 25 percent of patients suffering from North American blastomycosis have oral or nasal lesions.
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South American Blastomycosis (Lutz Disease): It is a fungal infection similar to its North American counterpart and is caused by the fungus Blastomyces brasiliensis. These organisms are typically found in the oral cavity's tooth periodontium (supporting tissue). It may also involve or spread to the regional lymph nodes. Periodontal infections, periapical granulomas (a collection of inflammatory tissue at tooth apex), and neck lymphadenopathy (swollen lymph nodes) are the oral manifestations of this infection.
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Rhinosporidiosis: Rhinosporiodosis is a chronic disease caused by the Rhinosporidium seeberi fungus that primarily affects the oral cavity, pharynx, skin, or genital mucosa. The characteristic features of this fungal disease are the tumor-like growths that are highly vascular and spread to the pharynx or larynx. However, the soft palate is the most affected area by Rhinosporiodosis in the oral cavity.
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Cysticercosis: These fungal infections are caused by Cysticercus species, with the larval forms infesting human beings. Cysticercosis has intraoral manifestations involving the lips, tongue, and cheeks. Further, a frequent finding is a single fluctuant oral mucocele-like lesion (mucocele is a cyst-like lesion) that can be found in affected individuals.
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Sporotrichosis: It is a fungal infection caused by Sporothrix schenckii by accidental or domestic exposure to the contaminated organism. The clinical features are skin lesions with ulcerative nodules or chancres (a painless ulcer). The oral manifestations of this disease may be intraoral or involve the mucosa of the larynx or pharynx. Furthermore, oral lesions in this disease are also associated with regional lymphadenopathy.
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Histoplasmosis: Histoplasmosis is a generalized fungal infection caused by the fungal organism Histoplasma capsulatum. It occurs by inhaling fungal spores from the contaminated excreta of pigeons, blackbirds, or starlings. Some characteristic features are chronic low-grade fever, splenomegaly (spleen enlargement), hepatomegaly (liver enlargement), and lymph node involvement. About 75 percent of these patients have severe oral manifestations with nodular, ulcerative, or vegetative lesions on the buccal mucosa, tongue, gingiva, lips, or palate.
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Coccidiomycosis: It is a common fungal infection caused by Coccidioides immitis that occurs specifically in endemic South Western regions of the United States or parts of Mexico, Central America, and Europe. Coccidiomycosis occurs by transmission of the fungal spores that contaminate dust and are inhaled by the individuals. Two different systemic forms of this disease involve multiorgan systems. The primary form of the disease manifests with cough, chest pain, and loss of appetite. On the other hand, the secondary form has a rapid course of infection that spreads from the lungs to the bones, joints, skin, and the central nervous system (CNS). Oral manifestations can be severe, as proliferative and granulomatous lesions in affected patients.
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Cryptococcosis: Cryptococcosis is also called European blastomycosis or torulosis. It is caused by the fungus Cryptococcus neoformans. It causes widespread lesions affecting the skin, oral cavity, brain, joints, and lungs. Cryptococcosis occurs by an airborne mechanism and presents as an opportunistic infection transmitted by inhalation of the infected fungal spores. The characteristic feature of this disease is that the meningeal involvement (layers of the brain) leads to complex neurological manifestations. Also, the affected patient has increased intracranial (in the brain) pressure. Oral lesions in these patients resemble those found in leukemia (cancer of the blood-forming tissues). They may manifest as single or multiple ulcerations in the mouth.
Conclusion:
To conclude, scientists have researched mycotic infections extensively over the last few decades. The dentist plays a major role in diagnosing and detecting mycotic oral cavity infections early. Further, timely diagnosis and treatment through topical and systemic medications can alleviate the disease symptoms. Severe lesions require surgical excision and elimination of predisposing risk factors. Also, proper oral hygiene is important in preventing oral mycotic infections.
