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Candidiasis

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Candidiasis
SpecialtyInfectious diseases, dermatology Edit this on Wikidata

Candidiasis, commonly called yeast infection or thrush, also known as "Candidosis," "Moniliasis," and "Oidiomycosis,"[1]: 308  is a fungal infection (mycosis) of any of the Candida species, of which Candida albicans is the most common.[2][3] Candidiasis encompasses infections that range from superficial, such as oral thrush and vaginitis, to systemic and potentially life-threatening diseases. Candida infections of the latter category are also referred to as candidemia and are usually confined to severely immunocompromised persons, such as cancer, transplant, and AIDS patients.

Superficial infections of skin and mucosal membranes by Candida causing local inflammation and discomfort are however common in many human populations.[3][4][5] While clearly attributable to the presence of the opportunistic pathogens of the genus Candida, candidiasis describes a number of different disease syndromes that often differ in their causes and outcomes.[3][4]

Manifestations

Most candidial infections are treatable and result in minimal complications such as redness, itching and discomfort, though complication may be severe or fatal if left untreated in certain populations. In immunocompetent persons, candidiasis is usually a very localized infection of the skin or mucosal membranes, including the oral cavity (thrush), the pharynx or esophagus, the gastrointestinal tract, the urinary bladder, or the genitalia (vagina, penis).[2]

Candidiasis is a very common cause of vaginal irritation, or vaginitis, and can also occur on the male genitals. In immunocompromised patients, Candida infections can affect the esophagus with the potential of becoming systemic, causing a much more serious condition, a fungemia called candidemia.[4][5]

Children, mostly between the ages of three and nine years of age, can be affected by chronic mouth yeast infections, normally seen around the mouth as white patches. However, this is not a common condition.[citation needed]

Types

Candidiasis may be divided into the following types:[1]: 308–311 

Causes

File:Oralcandi.JPG
Oral candidiasis on the tongue and soft palate.

Candida yeasts are commonly present in humans, and their growth is normally limited by the human immune system and by other microorganisms, such as bacteria occupying the same locations (niches) in the human body [6]

In a study of 1009 women in New Zealand, C. albicans was isolated from the vaginas of 19% of apparently healthy women, i.e., those that experienced few or no symptoms of infection. External use of detergents or douches or internal disturbances (hormonal or physiological) can perturb the normal vaginal flora, consisting of lactic acid bacteria, such as lactobacilli, and result in an overgrowth of Candida cells causing symptoms of infection, such as local inflammation.[7] Pregnancy and the use of oral contraceptives have been reported as risk factors,[8] while the roles of engaging in vaginal sex immediately and without cleansing after anal sex and using lubricants containing glycerin remain controversial.[citation needed] Diabetes mellitus and the use of anti-bacterial antibiotics are also linked to an increased incidence of yeast infections.[8] Diet has been found to affect rates of symptomatic Candidiases in some animal infection models, [9] and hormone replacement therapy and infertility treatments may also be predisposing factors.[10]

A weakened or undeveloped immune system or metabolic illnesses such as diabetes are significant predisposing factors of candidiasis.[11] Diseases or conditions linked to candidiasis include HIV/AIDS, mononucleosis, cancer treatments, steroids, stress, and nutrient deficiency. Almost 15% of people with weakened immune systems develop a systemic illness caused by Candida species.[citation needed] In extreme cases, these superficial infections of the skin or mucous membranes may enter into the bloodstream and cause systemic Candida infections.

In penile candidiasis, the causes include sexual intercourse with an infected individual, low immunity, antibiotics, and diabetes. Male genital yeast infection is less common, and incidence of infection is only a fraction of that in women; however, yeast infection on the penis from direct contact via sexual intercourse with an infected partner is not uncommon.[12]

Symptoms

Symptoms of candidiasis may vary depending on the area affected. Infection of the vagina or vulva may cause severe itching, burning, soreness, and irritation, and a whitish or whitish-gray discharge, often with a curd-like appearance. These symptoms are also present in the more common bacterial vaginosis[citation needed]. In a 2002 study published in the Journal of Obstetrics and Gynecology,[where?] only 33 percent of women who were self-treating for a yeast infection actually had a yeast infection, while most had either bacterial vaginosis or a mixed-type infection. Symptoms of infection of the male genitalia include red patchy sores near the head of the penis or on the foreskin, severe itching, or a burning sensation. Candidiasis of the penis can also have a white discharge, although uncommon.[citation needed] However, having no symptoms at all is common, and a more severe form of the symptoms may emerge later.[citation needed]

Diagnosis

Micrograph of esophageal candidiasis. Biopsy specimen; PAS stain.

Medical professionals may use two primary methods to diagnose yeast infections: microscopic examination and culturing.

For identification by light microscopy, a scraping or swab of the affected area is placed on a microscope slide. A single drop of 10% potassium hydroxide (KOH) solution is then added to the specimen. The KOH dissolves the skin cells but leaves the Candida cells intact, permitting visualization of hyphae and yeast cells typical of many Candida species.

For the culturing method, a sterile swab is rubbed on the infected skin surface. The swab is then streaked on a culture medium. The culture is incubated at 37 °C for several days, to allow development of yeast or bacterial colonies. The characteristics (such as morphology and colour) of the colonies may allow initial diagnosis of the organism that is causing disease symptoms.

Treatment

Candida species are frequently part of the human body's normal oral and intestinal flora. Treatment with antibiotics can lead to eliminating the yeast's natural competitors for resources, and increase the severity of the condition.

In clinical settings, candidiasis is commonly treated with antimycotics—the antifungal drugs commonly used to treat candidiasis are topical clotrimazole, topical nystatin, fluconazole, and topical ketoconazole. For example, a one-time dose of fluconazole (as Diflucan 150-mg tablet taken orally) has been reported as being 90% effective in treating a vaginal yeast infection.[13] This dose is only effective for vaginal yeast infections, and other types of yeast infections may require different treatments. In severe infections (generally in hospitalized patients), amphotericin B, caspofungin, or voriconazole may be used. Local treatment may include vaginal suppositories or medicated douches. Gentian violet can be used for breastfeeding thrush, but pediatrician William Sears recommends using it sparingly,[14] since in large quantities it can cause mouth and throat ulcerations in nursing babies, and has been linked to mouth cancer in humans and to cancer in the digestive tract of other animals.[15]

Treating candidiasis solely with medication may not give desired results, and other underlying conditions may be the cause. Oral candidiasis can be the sign of a more serious condition, such as HIV infection or other immunodeficiency diseases. Maintaining vulvovaginal health can help prevent vaginal candidiasis.

C. albicans can develop resistance to antimycotic drugs, [16] such as fluconazole, one of the drugs that is often used to treat candidiasis. Recurring infections may be treatable with other anti-fungal drugs, but resistance to these alternative agents may also develop.

History and taxonomic classification

See also: Candida albicans

The genus Candida and species C. albicans was described by botanist Christine Marie Berkhout in her doctoral thesis at the University of Utrecht in 1923. Over the years, the classification of the genera and species has evolved. Obsolete names for this genus include Mycotorula and Torulopsis. The species has also been known in the past as Monilia albicans and Oidium albicans. The current classification is nomen conservandum, which means the name is authorized for use by the International Botanical Congress (IBC).[17]

The genus Candida includes about 150 different species, however, only a few are known to cause human infections: C. albicans is the most significant pathogenic species. Other Candida species pathogenic in humans include C. tropicalis, C. glabrata, C. krusei, C. parapsilosis, C. dubliniensis, and C. lusitaniae.

Alternative views

Some alternative medicine proponents postulate a widespread occurrence of "systemic candidiasis" (or candida hypersensitivity syndrome, yeast allergy, or gastrointestinal candida overgrowth). The view was most widely promoted in a book published by Dr. William Crook,[18] which hypothesized that a variety of common symptoms such as fatigue, PMS, sexual dysfunction, asthma, psoriasis, digestive and urinary problems, multiple sclerosis, and muscle pain, could be caused by subclinical infections of Candida albicans.[citation needed] Crook suggested a variety of remedies to treat these symptoms, ranging from dietary modification, prescription antifungals, to colonic irrigation. With the exception of the few dietary studies in the urinary tract infection section conventional medicine has not used most of these alternatives, since there is limited scientific evidence to prove their effectiveness, or that subclinical "systemic candidiasis" is a viable diagnosis.[19][20]

References

  1. ^ a b James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0. {{cite book}}: Explicit use of et al. in: |author= (help)CS1 maint: multiple names: authors list (link)
  2. ^ a b Walsh TJ, Dixon DM (1996). "Deep Mycoses". In Baron S et al eds. (ed.). Baron's Medical Microbiology (via NCBI Bookshelf) (4th ed.). Univ of Texas Medical Branch. ISBN 0-9631172-1-1. {{cite book}}: |editor= has generic name (help)
  3. ^ a b c MedlinePlus Encyclopedia: Vaginal yeast infection
  4. ^ a b c Fidel PL (2002). "Immunity to Candida". Oral Dis. 8: 69–75. doi:10.1034/j.1601-0825.2002.00015.x. PMID 12164664.
  5. ^ a b Pappas PG (2006). "Invasive candidiasis". Infect. Dis. Clin. North Am. 20 (3): 485–506. doi:10.1016/j.idc.2006.07.004. PMID 16984866.
  6. ^ Mulley, A. G.; Goroll, A. H. (2006). Primary Care Medicine: office evaluation and management of the adult patient. Philadelphia: Wolters Kluwer Health. pp. 802–3. ISBN 0-7817-7456-X. Retrieved 2008-11-23.{{cite book}}: CS1 maint: multiple names: authors list (link)
  7. ^ Mårdh P A, Novikova N, Stukalova E (2003). "Colonisation of extragenital sites by Candida in women with recurrent vulvovaginal candidosis". BJOG. 110 (10): 934–7. PMID 14550364. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  8. ^ a b Schiefer HG (1997). "Mycoses of the urogenital tract". Mycoses. 40 Suppl 2: 33–6. PMID 9476502.
  9. ^ Yamaguchi N, Sonoyama K, Kikuchi H, Nagura T, Aritsuka T, Kawabata J (2005). "Gastric colonization of Candida albicans differs in mice fed commercial and purified diets". J. Nutr. 135 (1): 109–15. PMID 15623841. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  10. ^ Nwokolo N C, Boag F C (2000). "Chronic vaginal candidiasis. Management in the postmenopausal patient". Drugs Aging. 16 (5): 335–9. PMID 10917071. {{cite journal}}: Unknown parameter |month= ignored (help)
  11. ^ Odds FC (1987). "Candida infections: an overview". Crit. Rev. Microbiol. 15 (1): 1–5. PMID 3319417.
  12. ^ David LM, Walzman M, Rajamanoharan S (1997). "Genital colonisation and infection with candida in heterosexual and homosexual males". Genitourin Med. 73 (5): 394–6. PMC 1195901. PMID 9534752. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  13. ^ Moosa MY, Sobel JD, Elhalis H, Du W, Akins RA (2004). "Fungicidal activity of fluconazole against Candida albicans in a synthetic vagina-simulative medium". Antimicrob. Agents Chemother. 48 (1): 161–7. doi:10.1128/AAC.48.1.161-167.2004. PMID 14693534.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  14. ^ "Thrush". www.askdrsears.com.
  15. ^ Craigmill A (1991). "Gentian Violet Policy Withdrawn". Cooperative Extension University of California -- Environmental Toxicology Newsletter. 11 (5). {{cite journal}}: Unknown parameter |month= ignored (help)
  16. ^ Cowen LE, Nantel A, Whiteway MS; et al. (2002). "Population genomics of drug resistance in Candida albicans". Proc. Natl. Acad. Sci. U.S.A. 99 (14): 9284–9. doi:10.1073/pnas.102291099. PMC 123132. PMID 12089321. {{cite journal}}: Explicit use of et al. in: |author= (help); Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  17. ^ "International Code of Botanical Nomenclature". Königstein. 2000. ISBN 3-904144-22-7. Retrieved 2008-11-23.
  18. ^ Crook, William G. (1986). The yeast connection: a medical breakthrough. New York: Vintage Books. ISBN 0394747003.
  19. ^ Weil A (2002-10-25). "Concerned About Candidiasis?". Weil Lifestyle. Retrieved 2008-02-21.
  20. ^ Barrett S (2005-10-08). "Dubious "Yeast Allergies"". QuackWatch. Retrieved 2008-02-21.

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