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Candidiasis Classification and external resources
Agar plate culture of Candida albicans
ICD-10	B37.
ICD-9	112
DiseasesDB	1929
MedlinePlus	001511
eMedicine	med/264  emerg/76 ped/312 derm/67
MeSH	D002177

Candidiasis, commonly called yeast infection or thrush, is a fungal infection (mycosis) of any of the Candida species, of which Candida albicans is the most common.¹²

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.²³⁴ 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.²³

Contents 1 Manifestation 2 Causes 3 Symptoms 4 Diagnosis 5 Treatment 6 History and taxonomic classification 7 Alternative views 8 References 9 External links 9.1 Images

Manifestation

Yeast infections may be fatal if left untreated in certain populations but most are treatable and result in minimal complications (such as redness, itching and discomfort). In immunocompetent persons, candidiasis is usually a very localized infection of the skin or mucosal membranes, including:¹

• the oral cavity (oral thrush)
• the pharynx
• the esophagus
• the navel
• the intestines
• the urinary bladder
• the vagina

Candidiasis is a very common cause of vaginal irritation, or vaginitis, and can also occur on the male genitals. In immunocompromised patients, the Candida infection can affect the esophagus with the potential of becoming systemic, causing a much more serious condition, a fungemia called candidemia.⁴³

Children, mostly between the ages of 3 and 9 years, 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}

Especially when the immune system is compromised, candidiasis can affect the the whole body, which is called a "systemic candidiasis" (fungemia).

Causes

Candida yeasts are usually present in most people, but uncontrolled multiplication resulting in disease symptoms is kept in check by other naturally occurring microorganisms, e.g., bacteria co-existing with the yeasts in the same locations, and by the human immune system.^{citation needed}

In a study of 1009 women in New Zealand, Candida albicans was isolated from the vaginas of 19% of apparently healthy women. Carriers experienced few or no symptoms. However, external use of irritants (such as some detergents or douches) or internal disturbances (hormonal or physiological) can perturb the normal flora, constituting lactic acid bacteria, such as lactobacilli, and an overgrowth of yeast can result in noticeable symptoms.^{citation needed} Pregnancy,^{citation needed} the use of oral contraceptives,^{citation needed} engaging in vaginal sex immediately and without cleansing after anal sex,^{citation needed} and using lubricants containing glycerin have been found to be causally related to yeast infections^{citation needed}. Diabetes mellitus and the use of antibiotics are also linked to an increased incidence of yeast infections.^{citation needed} Diet has been found to be the cause in some animals. Hormone Replacement Therapy and infertility treatments may also be predisposing factors.^{citation needed}

A weakened or undeveloped immune system or metabolic illnesses such as diabetes may predispose individuals to candidiasis.⁵ Diseases or conditions linked to candidiasis include HIV/AIDS, mononucleosis, cancer treatments, steroids, stress, and nutrient deficiency, among many others. 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.

Antibiotic and steroid use are the most common reason for yeast overgrowth.⁶ The former kills the bacteria which would otherwise help maintain Candida at safe levels, thus allowing the fungus to overgrow.

Since the Candida fungus thrives in warm, moist, and dark places, exposed areas with these conditions such as the mouth, skin folds, armpits, and vagina are more vulnerable.

In penile candidiasis, the causes include sexual intercourse with an infected party, low immunity, antibiotics, and diabetes. However, male yeast infection is less common, and the risk of getting it is only a fraction of that in women.^{citation needed} However, yeast infection on the penis from direct contact via sexual intercourse with an infected woman is not uncommon.^{citation needed}

Symptoms

Symptoms include severe itching, burning, and soreness, irritation of the vagina and/or vulva, and a whitish or whitish-gray discharge, often with a curd-like appearance.

Many women mistake the symptoms of the more common bacterial vaginosis for a yeast infection. In a 2002 study published in the Journal of Obstetrics and Gynecology, 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 instead.

In men, symptoms include red patchy sores near the head of the penis or on the foreskin, severe itching, and/or a burning sensation. Candidiasis of the penis can also have a white discharge, although uncommon. However, having no symptoms at all is common, and usually, a more severe form of the symptoms may emerge later.

Diagnosis

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

It is important to consider that 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.⁷ 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,⁸ 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.⁹

While home remedies may offer relief in minor cases of infection, seeking medical attention may be necessary, especially if the extent of the infection cannot be judged accurately by the patient. For instance, oral thrush is visible only at the upper digestive tract, but it may be that the lower digestive tract is likewise colonized by Candida species.

Treating candidiasis solely with medication may not give desired results, and other underlying causes require consideration. For example, oral candidiasis can also be the sign of a more serious condition, such as HIV infection or other immunodeficiency diseases. Maintaining vulvovaginal health can help prevent vaginal candidiasis.

It is possible for Candida Albicans to develop a resistance to the drugs used to treat it, as seen from research done¹⁰ involving fluconazole, one of the drugs that is used to treat candidiasis. In this case, the recurring infection would have to use a different prescription, and it is possible that resistance is slowly built to many of the available medications used to treat the yeast infection.

Babies with diaper rash should have their diaper areas kept clean, dry, and exposed to air as much as possible. Sugars assist the overgrowth of yeast, possibly explaining the increased prevalence of yeast infections in patients with diabetes mellitus, as noted above. As many Candida spp. reside in the digestive tract, dietary changes may be effective for preventing or during a Candida infection. Due to its requirement for readily-fermentable carbon sources, such as mono- or dimeric sugars (e.g., sucrose, glucose, lactose) and starch, avoiding foods that contain these nutrients in high abundance may help to prevent excessive Candida growth.

History and taxonomic classification

The genus Candida, species albicans was described by botanist Christine Marie Berkhout. She described the fungus 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).

The full current taxonomic classification is available at Candida albicans.

The genus Candida includes about 150 different species. However, only a few of those are known to cause human infections. C. albicans is the most significant pathogenic (=disease-causing) species. Other Candida species causing diseases 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". The view was promoted in a book published by Dr. William Crook,¹¹ 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 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.¹²¹³

References

External links

• National Institute of Allergies and Infections (2007-06-27). "Vaginitis". Retrieved on 2008-02-21. - fact sheet on vaginitis/vaginal infections

• Candidiasis at eMedicine

• Oral Thrush Mayo Clinic

Images

• DermAtlas candidiasis images
• Links to pictures of Yeast Infection (Hardin MD/Univ of Iowa)

v • d • e Diseases of the skin and appendages by morphology Growths Epidermal verruca, clavus, seborrheic keratosis, acrochordon, molluscum contagiosum, actinic keratosis, squamous cell carcinoma, basal cell carcinoma, merkel cell carcinoma, nevus sebaceous, trichoepithelioma Pigmented ephelis, lentigo, melasma, nevus, malignant melanoma Dermal and subcutaneous epidermal inclusion cyst, hemangioma, dermatofibroma, keloid, lipoma, neurofibroma, xanthoma, Kaposi's sarcoma, infantile digital fibromatosis, granular cell tumor, leiomyoma, lymphangioma circumscriptum, myxoid cyst Rashes With epidermal involvement Eczematous essential dermatitis, contact dermatitis, atopic dermatitis, seborrheic dermatitis, stasis dermatitis, lichen simplex chronicus, Darier's disease, glucagonoma syndrome, langerhans cell histiocytosis, lichen sclerosus, pemphigus foliaceus, Wiskott-Aldrich syndrome, Zinc deficiency Scaling psoriasis, tinea corporis, tinea cruris, tinea pedis, tinea manuum, tinea faciale, pityriasis rosea, secondary syphillis, mycosis fungoides, systemic lupus erythematosus, pityriasis rubra pilaris, parapsoriasis, icthyosis Blistering herpes simplex, herpes zoster, varicella, bullous impetigo, acute contact dermatitis, pemphigus vulgaris, bullous pemphigoid, dermatitis herpetiformis, porphyria cutanea tarda, epidermolysis bullosa simplex Papular scabies, insect bite reactions, lichen planus, miliaria, keratosis pilaris, lichen spinulosus, transient acantholytic dermatosis, lichen nitidus, pityriasis lichenoides et varioliformis acuta Pustular acne vulgaris, acne rosacea, folliculitis, impetigo, candidiasis, gonococcemia, dermatophyte, coccidioidomycosis, subcorneal pustular dermatosis Hypopigmented tinea versicolor, vitiligo, pityriasis alba, postinflammatory hypopigmentation, tuberous sclerosis, idiopathic guttate hypomelanosis, leprosy, hypopigmented mycosis fungoides Without epidermal involvement Red Blanchable Erythema Generalized drug eruptions, viral exanthems, toxic erythema, systemic lupus erythematosus Localized cellulitis, abscess, furuncle, erythema nodosum, carcinoid syndrome, carcinoma erysipeloides, fixed drug eruption Specialized urticaria, erythema multiforme, erythema migrans, erythema gyratum repens, erythema annulare centrifugum, erythema ab igne Nonblanchable Purpura Macular thrombocytopenic purpura, actinic purpura Papular disseminated intravascular coagulation, vasculitis Indurated scleroderma/morphea, granuloma annulare, lichen sclerosis et atrophicus, necrobiosis lipoidica Miscellaneous Ulcers Hair disorders telogen effluvium, androgenic alopecia, trichotillomania, alopecia areata, systemic lupus erythematosus, tinea capitis, loose anagen syndrome, lichen planopilaris, folliculitis decalvans, acne keloidalis nuchae Nail disorders onychomycosis, psoriasis, paronychia, ingrown nail Mucous membrane disorders aphthous stomatitis, oral candidiasis, lichen planus, leukoplakia, pemphigus vulgaris, mucous membrane pemphigoid, cicatricial pemphigoid, herpesvirus, coxsackievirus, syphilis, systemic histoplasmosis, squamous cell carcinoma

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