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<unk>  cases, and together C. albicans, C. tropicalis and C. glabrata account for over 80% of cases.<unk>  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<unk>  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.<unk>  carriage of Candida is pre-requisite for the development of<unk> . For Candida species to colonize and survive as a normal component of the<unk>  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 to HIV/AIDS, diabetes, cancer, Down syndrome or malnutrition). Age also influences<unk>  carriage, with the lowest levels<unk> curring in newborns, increasing dramatically in infants, and then decreasing again in adults. Investigations have quantified<unk>  carriage of Candida albicans at 300-500 colony forming units in healthy persons. More Candida is detected in the early morning and the late afternoon. The greatest quantity of Candida species are harbored on the posterior dorsal tongue, followed by the palatal and the buccal mucosae. Mucosa covered by an<unk>  appliance such as a denture harbors significantly more candida species than uncovered mucosa. When Candida species cause lesions - the result of invasion of the host tissues - this is termed<unk> . Some consider<unk>  a change in the normal<unk>  environment rather than an exposure or true "infection" as such. The exact process by which Candida species switch from acting as normal<unk>  commensals (saprophytic) state in the carrier to acting as a pathogenic organism (parasitic state) is not completely understood. Several Candida species are polymorphogenic, that is, capable of growing in different forms depending on the environmental conditions. C. albicans can appear as a yeast form (blastospores), which is thought to be relatively harmless; and a hyphal form associated with invasion of host tissues. Apart from true hyphae, Candida can also form pseudohyphae — elongated filamentous cells, lined end to end. As a general rule,<unk>  presenting with white lesions is mainly caused by Candida species in the hyphal form and red lesions by yeast forms. C. albicans and C. dubliniensis are also capable of forming germ tubes (incipient hyphae) and chlamydospores under the right conditions. C. albicans is categorized serologically into A or B serotypes. The prevalence is roughly equal in healthy individuals, but type B is more prevalent in immunocompromised individuals. Predisposing factors + Common local and systemic predisposing factors. Local host factors *Dentures *Corticosteroid inhalers *Reduced salivary flow *High sugar diet Systemic host factors *Extremes of age *Endocrine disorders (e.g., diabetes) *Immunosuppression *Broad spectrum antibiotics (e.g., tetracycline) *Nutritional deficiencies The host defenses against opportunistic infection of candida species are *The<unk>  epithelium, which acts both as a physical barrier preventing micro-organisms from entering the tissues, and is the site of cell mediated immune reactions. *Competition and inhibition interactions between candida species and other micro-organisms in the mouth, such as the many hundreds of different kinds of bacteria. *Saliva, which possesses both mechanical cleansing action and immunologic action, including salivary immunoglobulin A antibodies, which aggregate candida organisms and prevent them adhering to the epithelial surface; and enzymatic components such as lysozyme, lactoperoxidase and antileukoprotease. Disruption to any of these local and systemic host defense mechanisms constitutes a potential susceptibility to<unk> , which rarely<unk> curs without predisposing factors. It is often described as being "a disease of the diseased",<unk> curring in the very young, the very old, or the very sick.<unk>  in an infant. At very young ages, the immune system is yet to develop fully. Immunodeficiency Immunodeficiency is a state of reduced function of the immune system, which can be caused by medical conditions or treatments. Acute pseudomembranous<unk> <unk> curs in about 5% of newborn infants. Candida species are acquired from the mother's vaginal canal during birth. At very young ages, the immune system is yet to develop fully and there is no individual immune response to candida species, an infants antibodies to the fungus are normally supplied by the mother's breast milk. Other forms of immunodeficiency which may cause<unk>  include HIV/AIDS, active cancer and treatment, chemotherapy or radiotherapy. Corticosteroid medications may contribute to the appearance of<unk> , as they cause suppression of immune function either systemically or on a local/mucosal level, depending on the route of administration. Topically administered corticosteroids in the mouth may take the form of mouthwashes, dissolving lozenges or mucosal gels; sometimes being used to treat various forms of stomatitis. Systemic corticosteroids may also result in<unk> . Inhaled corticosteroids (e.g., for treatment of asthma or chronic obstructive pulmonary disease), are not intended to be administered topically in the mouth, but inevitably there is contact with the<unk>  and oropharyngeal mucousa as it is inhaled. In asthmatics treated with inhaled steroids, clinically detectable<unk>  may<unk> cur in about 5-10% of adults and 1% of children. Where inhaled steroids are the cause, the candidal lesions are usually of the erythematous variety.<unk>  appears at the sites where the steroid has contacted the mucosa, typically the dorsum of the tongue (median rhomboid glossitis) and sometimes also on the palate. Candidal lesions on both sites are sometimes termed "kissing lesions" because they approximate when the tongue is in contact with the palate. Denture wearing Denture wearing and poor denture hygiene, particularly wearing the denture continually rather than removing it during sleep, is another risk factor for both candidal carriage and<unk> . Dentures provide a relative acidic, moist and anaerobic environment because the mucosa covered by the denture is sheltered from oxygen and saliva. Loose, poorly fitting dentures may also cause minor trauma to the mucosa, which is thought to increase the permeability of the mucosa and increase the ability of C. albicans to invade the tissues. These conditions all favor the growth of C. albicans. Sometimes dentures become very worn, or they have been constructed to allow insufficient lower facial height <unk> clusal vertical dimension), leading to over-closure of the mouth (an appearance sometimes described as "collapse of the jaws"). This causes deepening of the skin folds at the corners of the mouth (nasolabial crease), in effect creating intertriginous areas where another form of<unk> , angular cheilitis, can develop. Candida species are capable of adhering to the surface of dentures, most of which are made from polymethylacrylate. They exploit micro-fissures and cracks in the surface of dentures to aid their retention. Dentures may therefore become covered in a biofilm, and act as reservoirs of infection, continually re-infecting the mucosa. For this reason, disinfecting the denture is a vital part of treatment of<unk>  in persons who wear dentures, as well as correcting other factors like inadequate lower facial height and fit of the dentures. Dry mouth Both the quantity and quality of saliva are important<unk>  defenses against candida. Decreased salivary flow rate or a change in the composition of saliva, collectively termed salivary hypofunction or hyposalivation is an important predisposing factor. Xerostomia is frequently listed as a cause of<unk> , but xerostomia can be subjective or objective, i.e., a symptom present with or without actual changes in the saliva consistency or flow rate. Diet Malnutrition, whether by malabsorption, or poor diet, especially hematinic deficiencies (iron, vitamin B12, folic acid) can predispose to<unk> , by causing diminished host defense and epithelial integrity. For example, iron deficiency anemia is thought to cause depressed cell-mediated immunity. Some sources state that deficiencies of vitamin A or pyridoxine are also linked. There is limited evidence that a diet high in carbohydrates predisposes to<unk> . In vitro and studies show that Candidal growth, adhesion and biofilm formation is enhanced by the presence of carbohydrates such as glucose, galactose and sucrose. Smoking Smoking, especially heavy smoking, is an important predisposing factor but the reasons for this relationship are unknown.
Oral candidiasis
Geographic tongue
Denture-related stomatitis
Leukoplakia
Contact stomatitis
Aphthous stomatitis
Caviar tongue
Head lice infestation