Oral candidiasis
Oral candidiasis | |
---|---|
Other names | oral candidosis, oral thrush, Infectious disease, dentistry, dermatology |
Oral candidiasis, also known as oral thrush among other names,
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.[3] 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.[2] |
---|
|
|
Classification of oral candidiasis.[2] |
|
Oral candidiasis is a
By appearance
Three main clinical appearances of candidiasis are generally recognized: pseudomembranous, erythematous (atrophic) and hyperplastic.[4] Most often, affected individuals display one clear type or another, but sometimes there can be more than one clinical variant in the same person.[5]
Pseudomembranous
Acute pseudomembranous candidiasis is a classic form of oral candidiasis,[6] commonly referred to as thrush.[4] Overall, this is the most common type of oral candidiasis,[7] accounting for about 35% of oral candidiasis cases.[8]
It is characterized by a coating or individual patches of pseudomembranous white slough that can be easily wiped away to reveal
It is classically an acute condition, appearing in infants, people taking antibiotics or immunosuppressant medications, or immunocompromising diseases.[6] 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.[4] Acute and chronic pseudomembranous candidiasis are indistinguishable in appearance.[6]
Erythematous
Erythematous (atrophic) candidiasis is when the condition appears as a red, raw-looking lesion.[8] 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.[6] Some sources state that erythematous candidiasis accounts for 60% of oral candidiasis cases.[8] 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.[6] On the tongue, there is loss of the lingual papillae (depapillation), leaving a smooth area.[5]
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.[9] This is usually termed "antibiotic sore mouth", "antibiotic sore tongue",[9] 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).[citation needed]
Hyperplastic
This variant is also sometimes termed "plaque-like candidiasis" or "nodular candidiasis".
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.[11] 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.[10] 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.[citation needed]
Associated lesions
Candida-associated lesions are primary oral candidiases (confined to the mouth), where the causes are thought to be multiple.[4] For example, bacteria as well as Candida species may be involved in these lesions.[6] 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.[4]
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",
This term refers to a mild inflammation and erythema of the mucosa beneath a
Median rhomboid glossitis
This is an elliptical or rhomboid lesion in the center of the dorsal tongue, just anterior (in front) of the
Linear gingival erythema
This is a localized or generalized, linear band of erythematous
Others
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.[13]
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.[6]
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.
Causes
Species
The causative organism is usually
About 35-50% of humans possess C. albicans as part of their normal oral
When Candida species cause lesions - the result of invasion of the host tissues - this is termed candidiasis.[2][19] Some consider oral candidiasis a change in the normal oral environment rather than an exposure or true "infection" as such.[7] The exact process by which Candida species switch from acting as normal oral commensals (saprophytic) state in the carrier to acting as a pathogenic organism (parasitic state) is not completely understood.[6]
Several Candida species are polymorphogenic,
Predisposing factors
Local host factors
|
Systemic host factors
|
The host defenses against opportunistic infection of candida species are
- The oral 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.[13]
Disruption to any of these local and systemic host defense mechanisms constitutes a potential susceptibility to oral candidiasis, which rarely occurs without predisposing factors.[4] It is often described as being "a disease of the diseased",[2][4] occurring in the very young, the very old, or the very sick.[4][6][21]
Immunodeficiency
Immunodeficiency is a state of reduced function of the immune system, which can be caused by medical conditions or treatments.
Acute pseudomembranous candidiasis occurs in about 5% of
Other forms of immunodeficiency which may cause oral candidiasis include
Corticosteroid medications may contribute to the appearance of oral candidiasis,[24] 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 candidiasis.
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 oral and oropharyngeal mucousa as it is inhaled. In asthmatics treated with inhaled steroids, clinically detectable oral candidiasis may occur in about 5-10% of adults and 1% of children.[25] Where inhaled steroids are the cause, the candidal lesions are usually of the erythematous variety.[6] Candidiasis 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.[26][27] Candidal lesions on both sites are sometimes termed "kissing lesions"[26][27] because they approximate when the tongue is in contact with the palate.
Denture wearing
Dry mouth
Both the quantity and quality of saliva are important oral defenses against candida.[6] Decreased salivary flow rate or a change in the composition of saliva,[8] collectively termed salivary hypofunction or hyposalivation is an important predisposing factor. Xerostomia is frequently listed as a cause of candidiasis,[3] 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
There is limited evidence that a diet high in carbohydrates predisposes to oral candidiasis.[9] 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.[28]
Smoking
Smoking, especially heavy smoking, is an important predisposing factor but the reasons for this relationship are unknown. One hypothesis is that cigarette smoke contains nutritional factors for C. albicans, or that local epithelial alterations occur that facilitate colonization of candida species.[28]
Antibiotics
Broad-spectrum antibiotics (e.g. tetracycline) eliminate the competing bacteria and disrupt the normally balanced ecology of oral microorganisms,[5][6] which can cause antibiotic-induced candidiasis.[3]
Other factors
Several other factors can contribute to infection, including
Diagnosis
The diagnosis can typically be made from the clinical appearance alone,
Special investigations to detect the presence of candida species include oral swabs, oral rinse or oral smears.
Sometimes an underlying medical condition is sought, and this may include blood tests for full blood count and hematinics.
If a biopsy is taken, the histopathologic appearance can be variable depending upon the clinical type of candidiasis. Pseudomembranous candidiasis shows hyperplastic epithelium with a superficial parakeratotic desquamating (i.e., separating) layer.[32] Hyphae penetrate to the depth of the stratum spinosum,[4] and appear as weakly basophilic structures. Polymorphonuclear cells also infiltrate the epithelium, and chronic inflammatory cells infiltrate the lamina propria.[32]
Atrophic candidiasis appears as thin, atrophic epithelium, which is non-keratinized. Hyphae are sparse, and inflammatory cell infiltration of the epithelium and the lamina propria. In essence, atrophic candidiasis appears like pseudomembranous candidiasis without the superficial desquamating layer.[32]
Hyperplastic candidiasis is variable. Usually there is hyperplastic and acanthotic epithelium with parakeratosis. There is an inflammatory cell infiltrate and hyphae are visible. Unlike other forms of candidiasis, hyperplastic candidiasis may show dysplasia.[32]
Treatment
Oral candidiasis can be treated with topical
Underlying immunosuppression may be medically manageable once it is identified, and this helps prevent recurrence of candidal infections.
Patients who are immunocompromised, either with
If candidiasis is secondary to corticosteroid or antibiotic use, then use may be stopped, although this is not always a feasible option. Candidiasis secondary to the use of inhaled steroids may be treated by rinsing out the mouth with water after taking the steroid.[15] Use of a spacer device to reduce the contact with the oral mucosa may greatly reduce the risk of oral candidiasis.[25]
In recurrent oral candidiasis, the use of azole antifungals risks selection and enrichment of drug-resistant strains of candida organisms.[30] Drug resistance is increasingly more common and presents a serious problem in persons who are immunocompromised.[13]
The candidal load in the mouth can be reduced by improving oral hygiene measures, such as regular toothbrushing and use of anti-microbial mouthwashes.[18] Since smoking is associated with many forms of oral candidiasis, cessation may be beneficial.[medical citation needed]
Denture hygiene
Good denture hygiene involves regular cleaning of the dentures, and leaving them out of the mouth during sleep. This gives the mucosa a chance to recover, while wearing a denture during sleep is often likened to sleeping in one's shoes. In oral candidiasis, the dentures may act as a reservoir of Candida species known as denture stomatitis[35][36][37][7] which continually reinfects the mucosa once antifungal medication is stopped. Therefore, they must be disinfected as part of the treatment for oral candidiasis. There are commercial denture cleaner preparations for this purpose, but it is readily accomplished by soaking the denture overnight in a 1:10 solution of sodium hypochlorite (Milton, or household bleach).[7] Bleach may corrode metal components,[13] so if the denture contains metal, soaking it twice daily in chlorhexidine solution can be carried out instead. An alternative method of disinfection is to use a 10% solution of acetic acid (vinegar) as an overnight soak, or to microwave the dentures in 200mL water for 3 minutes at 650 watts.[13] Microwave sterilization is only suitable if no metal components are present in the denture. Antifungal medication can also be applied to the fitting surface of the denture before it is put back in the mouth. Other problems with the dentures, such as inadequate occlusal vertical dimension may also need to be corrected in the case of angular cheilitis.
Prognosis
The severity of oral candidiasis is subject to great variability from one person to another and in the same person from one occasion to the next.[8] The prognosis of such infection is usually excellent after the application of topical or systemic treatments. However, oral candidiasis can be recurrent.[8] Individuals continue to be at risk of the condition if underlying factors such as reduced salivary flow rate or immunosuppression are not rectifiable.[8]
Candidiasis can be a marker for underlying disease,[20] so the overall prognosis may also be dependent upon this. For example, a transient erythematous candidiasis that developed after antibiotic therapy usually resolves after antibiotics are stopped (but not always immediately),[15] and therefore carries an excellent prognosis—but candidiasis may occasionally be a sign of more sinister undiagnosed pathology, such as HIV/AIDS or leukemia.
It is possible for candidiasis to spread to/from the mouth, from sites such as the pharynx, esophagus, lungs, liver, anogenital region, skin or the nails.
The role of thrush in the hospital and ventilated patients is not entirely clear, however, there is a theoretical risk of positive interaction of candida with topical bacteria.[39]
Epidemiology
In humans, oral candidiasis is the most common form of candidiasis,[17] by far the most common fungal infection of the mouth,[5] and it also represents the most common opportunistic oral infection in humans[40] with lesions only occurring when the environment favors pathogenic behavior.
Oropharyngeal candidiasis is common during cancer care,[23] and it is a very common oral sign in individuals with HIV.[22] Oral candidiasis occurs in about two thirds of people with concomitant AIDS and esophageal candidiasis.[41]
The incidence of all forms of candidiasis have increased in recent decades. This is due to developments in medicine, with more invasive medical procedures and surgeries, more widespread use of broad spectrum antibiotics and immunosuppression therapies. The HIV/AIDs global
History
Oral candidiasis has been recognized throughout recorded history.
The colloquial term "thrush" refers to the resemblance of the white flecks present in some forms of candidiasis (e.g., pseudomembranous candidiasis), with the breast of the bird of the same name.[43]
Society and culture
Many pseudoscientific claims by proponents of alternative medicine surround the topic of candidiasis. Oral candidiasis is sometimes presented in this manner as a symptom of a widely prevalent systemic candidiasis, candida hypersensitivity syndrome, yeast allergy, or gastrointestinal candida overgrowth, which are medically unrecognized conditions.[citation needed](See: Alternative medicine in Candidiasis)
References
- ^ OCLC 62736861.
- ^ ISBN 9780443068188.
- ^ ISBN 9780199204830.
- ^ ISBN 978-0702041679.
- ^ ISBN 978-0721690032.
- ^ ISBN 9781550093452.
- ^ ISBN 978-1-60327-519-4.
- ^ PMID 22662470. Archived from the original(PDF) on 2013-11-02. Retrieved 2013-09-06.
- ^ ISBN 978-0192628947.
- ^ ISBN 9780443068966.
- PMID 12907694.
- PMID 21838086.
- ^ ISBN 9780702049484.
- ^ PMID 20711156.
- ^ ISBN 978-0192631473.
- ISBN 978-1-4377-0416-7.
- ^ ISBN 9788184484021.
- ^ PMID 21547018.
- ^ PMID 21801848.
- ^ PMID 7936588.
- PMID 7858080.
- ^ S2CID 6427809.
- ^ S2CID 8521191.
- ^ ISBN 9780443067846.
- ^ ISBN 9780203908532.
- ^ ISBN 9780199748273.
- ^ ISBN 9781461483540.
- ^ a b c d e Tarçın BG (2011). "Oral candidosis: aetiology, clinical manifestations, diagnosis and management" (PDF). MÜSBED. 1 (2): 140–148. Archived from the original (PDF) on 2022-05-02. Retrieved 2013-09-10.
- PMID 21463383.
- ^ S2CID 38426846.
- ^ PMID 22842360.
- ^ ISBN 9789350252147.
- PMID 28367031.
- PMID 17253497.
- PMID 10730723.
- PMID 26879270.
- PMID 34890423.
- S2CID 86182033.
- S2CID 8306886.
- S2CID 46516738.
- ISBN 978-1-4051-6911-0.
- ISBN 978-0-443-06839-3.
- ^ Scully C. "Mucosal Candidiasis (Medscape)". WebMD LLC. Retrieved 8 September 2013.