oral candidiasis oral candidiasis oral candidiasis, also known as oral thrush among other names, is candidiasis that occurs in the mouth. that is, oral candidiasis is a mycosis (yeast/fungal infection) of candida species on the mucous membranes of the mouth. oral candidiasisother namesoral candidosis, oral thrush, oropharyngeal candidiasis, moniliasis, candidal stomatitis, muguetoral candidiasisspecialtyinfectious disease, dentistry, dermatology candida albicans is the most commonly implicated organism in this condition. c. albicans is carried in the mouths of about 50% of the world's population as a normal component of the oral microbiota. this candidal carriage state is not considered a disease, but when candida species become pathogenic and invade host tissues, oral candidiasis can occur. this change usually constitutes an opportunistic infection by normally harmless micro-organisms because of local (i.e., mucosal) or systemic factors altering host immunity. classification traditional classification of oral candidiasis. acute candidiasis: pseudomembranous candidiasis (oral thrush) atrophic candidiasis chronic candidiasis: atrophic candidiasis hyperplastic candidiasis chronic oral candidiasis (candida leukoplakia) candidiasis endocrinopathy syndrome chronic localized mucocutaneous candidiasis chronic diffuse candidiasis. classification of oral candidiasis. primary oral candidiasis (group i) pseudomembranous (acute or chronic) erythematous (acute or chronic) hyperplastic: plaque-like, nodular candida-associated lesions: denture related stomatitis, angular stomatitis, median rhomboid glossitis, linear gingival erythema secondary oral candidiasis (group ii) oral manifestations of systemic mucocutaneous candidiasis (due to diseases such as thymic aplasia and candidiasis endocrinopathy syndrome) oral candidiasis is a mycosis (fungal infection). traditionally, oral candidiasis is classified using the lehner system, originally described in the 1960s, into acute and chronic forms (see table). some of the subtypes almost always occur as acute (e.g., acute pseudomembranous candidiasis), and others chronic. however, these typical presentations do not always hold true, which created problems with this system. a more recently proposed classification of oral candidiasis distinguishes primary oral candidiasis, where the condition is confined to the mouth and perioral tissues, and secondary oral candidiasis, where there is involvement of other parts of the body in addition to the mouth. the global human immunodeficiency virus/acquired immunodeficiency syndrome (hiv/aids) pandemic has been an important factor in the move away from the traditional classification since it has led to the formation of a new group of patients who present with atypical forms of oral candidiasis. by appearance three main clinical appearances of candidiasis are generally recognized: pseudomembranous, erythematous (atrophic) and hyperplastic. most often, affected individuals display one clear type or another, but sometimes there can be more than one clinical variant in the same person. pseudomembranous candidiasis in the mouth and oropharynx.pseudomembranous candidiasis in a person with hiv pseudomembranous acute pseudomembranous candidiasis is a classic form of oral candidiasis, commonly referred to as thrush. overall, this is the most common type of oral candidiasis, accounting for about 35% of oral candidiasis cases. it is characterized by a coating or individual patches of pseudomembranous white slough that can be easily wiped away to reveal erythematous (reddened), and sometimes minimally bleeding, mucosa beneath. these areas of pseudomembrane are sometimes described as "curdled milk", or "cottage cheese". the white material is made up of debris, fibrin, and desquamated epithelium that has been invaded by yeast cells and hyphae that invade to the depth of the stratum spinosum. as an erythematous surface is revealed beneath the pseudomembranes, some consider pseudomembranous candidiasis and erythematous candidiasis stages of the same entity. some sources state that if there is bleeding when the pseudomembrane is removed, then the mucosa has likely been affected by an underlying process such as lichen planus or chemotherapy. pseudomembraneous candidiasis can involve any part of the mouth, but usually it appears on the tongue, buccal mucosae or palate. it is classically an acute condition, appearing in infants, people taking antibiotics or immunosuppressant medications, or immunocompromising diseases. however, sometimes it can be chronic and intermittent, even lasting for many years. chronicity of this subtype generally occurs in immunocompromised states, (e.g., leukemia, hiv) or in persons who use corticosteroids topically or by aerosol. acute and chronic pseudomembranous candidiasis are indistinguishable in appearance. erythematous erythematous (atrophic) candidiasis is when the condition appears as a red, raw-looking lesion. some sources consider denture-related stomatitis, angular stomatitis, median rhomboid glossitis, and antiobiotic-induced stomatitis as subtypes of erythematous candidiasis, since these lesions are commonly erythematous/atrophic. it may precede the formation of a pseudomembrane, be left when the membrane is removed, or arise without prior pseudomembranes. some sources state that erythematous candidiasis accounts for 60% of oral candidiasis cases. where it is associated with inhalation steroids (often used for treatment of asthma), erythematous candidiasis commonly appears on the palate or the dorsum of the tongue. on the tongue, there is loss of the lingual papillae (depapillation), leaving a smooth area. acute erythematous candidiasis usually occurs on the dorsum of the tongue in persons taking long term corticosteroids or antibiotics, but occasionally it can occur after only a few days of using a topical antibiotic. this is usually termed "antibiotic sore mouth", "antibiotic sore tongue", or "antibiotic-induced stomatitis" because it is commonly painful as well as red. chronic erythematous candidiasis is more usually associated with denture wearing (see denture-related stomatitis). hyperplastic this variant is also sometimes termed "plaque-like candidiasis" or "nodular candidiasis". the most common appearance of hyperplastic candidiasis is a persistent white plaque that does not rub off. the lesion may be rough or nodular in texture. hyperplastic candidiasis is uncommon, accounting for about 5% of oral candidiasis cases, and is usually chronic and found in adults. the most common site of involvement is the commissural region of the buccal mucosa, usually on both sides of the mouth. another term for hyperplastic candidiasis is "candidal leukoplakia". this term is a largely historical synonym for this subtype of candidiasis, rather than a true leukoplakia. indeed, it can be clinically indistinguishable from true leukoplakia, but tissue biopsy shows candidal hyphae invading the epithelium. some sources use this term to describe leukoplakia lesions that become colonized secondarily by candida species, thereby distinguishing it from hyperplastic candidiasis. it is known that candida resides more readily in mucosa that is altered, such as may occur with dysplasia and hyperkeratosis in an area of leukoplakia. associated lesions candida-associated lesions are primary oral candidiases (confined to the mouth), where the causes are thought to be multiple. for example, bacteria as well as candida species may be involved in these lesions. frequently, antifungal therapy alone does not permanently resolve these lesions, but rather the underlying predisposing factors must be addressed, in addition to treating the candidiasis. angular cheilitis angular cheilitis main article: angular cheilitis angular cheilitis is inflammation at the corners (angles) of the mouth, very commonly involving candida species, when sometimes the terms "candida-associated angular cheilitis", or less commonly "monilial perlèche" are used. candida organisms alone are responsible for about 20% of cases, and a mixed infection of c. albicans and staphylococcus aureus for about 60% of cases. signs and symptoms include soreness, erythema (redness), and fissuring of one, or more commonly both the angles of the mouth, with edema (swelling) seen intraorally on the commissures (inside the corners of the mouth). angular cheilitis generally occurs in elderly people and is associated with denture related stomatitis. denture-related stomatitis main article: denture-related stomatitis this term refers to a mild inflammation and erythema of the mucosa beneath a denture, usually an upper denture in elderly edentulous individuals (with no natural teeth remaining). some report that up to 65% of denture wearers have this condition to some degree. about 90% of cases are associated with candida species, where sometimes the terms "candida-associated denture stomatitis", or "candida-associated denture-induced stomatitis" (cadis), are used. some sources state that this is by far the most common form of oral candidiasis. although this condition is also known as "denture sore mouth", there is rarely any pain. candida is associated with about 90% of cases of denture related stomatitis. median rhomboid glossitis median rhomboid glossitis main article: median rhomboid glossitis this is an elliptical or rhomboid lesion in the center of the dorsal tongue, just anterior (in front) of the circumvallate papillae. the area is depapillated, reddened (or red and white) and rarely painful. there is frequently candida species in the lesion, sometimes mixed with bacteria. linear gingival erythema main article: linear gingival erythema this is a localized or generalized, linear band of erythematous gingivitis (inflammation of the gums). it was first observed in hiv infected individuals and termed "hiv-gingivitis", but the condition is not confined to this group. candida species are involved, and in some cases the lesion responds to antifungal therapy, but it is thought that other factors exist, such as oral hygiene and human herpesviruses. this condition can develop into necrotizing ulcerative periodontitis. chronic multifocal oral candidiasis this is an uncommon form of chronic (more than one month in duration) candidal infection involving multiple areas in the mouth, without signs of candidiasis on other mucosal or cutaneous sites. the lesions are variably red and/or white. unusually for candidal infections, there is an absence of predisposing factors such as immunosuppression, and it occurs in apparently healthy individuals, normally elderly males. smoking is a known risk factor. chronic mucocutaneous candidiasis main article: chronic mucocutaneous candidiasis this refers to a group of rare syndromes characterized by chronic candidal lesions on the skin, in the mouth and on other mucous membranes (i.e., a secondary oral candidiasis). these include localized chronic mucocutaneous candidiasis, diffuse mucocutaneous candidiasis (candida granuloma), candidiasis–endocrinopathy syndrome and candidiasis thymoma syndrome. about 90% of people with chronic mucocutaneous candidiasis have candidiasis in the mouth. signs and symptoms signs and symptoms are dependent upon the type of oral candidiasis. often, apart from the appearance of the lesions, there are usually no other signs or symptoms. most types of oral candidiasis are painless, but a burning sensation may occur in some cases. candidiasis can, therefore, sometimes be misdiagnosed as burning mouth syndrome. a burning sensation is more likely with erythematous (atrophic) candidiasis, whilst hyperplastic candidiasis is normally entirely asymptomatic. acute atrophic candidiasis may feel like the mouth has been scalded with a hot liquid. another potential symptom is a metallic, acidic, salty or bitter taste in the mouth. the pseudomembranous type rarely causes any symptoms apart from possibly some discomfort or bad taste due to the presence of the membranes. sometimes the patient describes the raised pseudomembranes as "blisters." occasionally there can be dysphagia (difficulty swallowing), which indicates that the candidiasis involves the oropharynx or the esophagus, as well as the mouth. the trachea and the larynx may also be involved where there is oral candidiasis, and this may cause hoarseness of the voice. causes species the causative organism is usually candida albicans, or less commonly other candida species such as (in decreasing order of frequency) candida tropicalis, candida glabrata, candida parapsilosis, candida krusei, or other species (candida stellatoidea, candida pseudotropicalis, candida famata, candida rugosa, candida geotrichium, candida dubliniensis, and candida guilliermondii). c. albicans accounts for about 50% of oral candidiasis cases, and together c. albicans, c. tropicalis and c. glabrata account for over 80% of cases. candidiasis caused by non-c. albicans candida (ncac) species is associated more with immunodeficiency. for example, in hiv/aids, c. dubliniensis and c. geotrichium can become pathogenic. about 35-50% of humans possess c. albicans as part of their normal oral microbiota. with more sensitive detection techniques, this figure is reported to rise to 90%. this candidal carrier state is not considered a disease, since there are no lesions or symptoms of any kind. oral carriage of candida is pre-requisite for the development of oral candidiasis. for candida species to colonize and survive as a normal component of the oral microbiota, the organisms must be capable of adhering to the epithelial surface of the mucous membrane lining the mouth. this adhesion involves adhesins (e.g., hyphal wall protein 1), and extracellular polymeric materials (e.g., mannoprotein). therefore, strains of candida with more adhesion capability have more pathogenic potential than other strains. the prevalence of candida carriage varies with geographic location, and many other factors. higher carriage is reported during the summer months, in females, in hospitalized individuals, in persons with blood group o and in non-secretors of blood group antigens in saliva. increased rates of candida carriage are also found in people who eat a diet high in carbohydrates, people who wear dentures, people with xerostomia (dry mouth), in people taking broad spectrum antibiotics, smokers, and in immunocompromised individuals (e.g., due