Candidiasis

Candidiasis is a disease of the skin, nails and mucous membranes, sometimes internal organs, caused by yeast-like fungi of the genus Candida.

The most significant role in human pathology is played by the Candida albicans fungus. Much less frequently, pathological changes can be caused by other fungi of this genus (Candida tropicalis, Candida krtisei, etc.).

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Cause of candidiasis

Yeast-like fungi of the genus Candida are opportunistic, non-spore-forming dimorphic fungi that are facultative anaerobes. They tolerate drying and freezing well. In the yeast phase of development, characteristic of saprophytic existence, they are unicellular, oval-shaped microorganisms, ranging in size from 1.5 μm (young cells to 14 μm (mature cells). They reproduce by multipolar budding. When invading tissues, Candida fungi often transform into thin filamentous forms, forming pseudomycelium as a result of incomplete budding of elongated yeast cells. In this case, the formed daughter cell maintains a connection with the mother cell due to a narrow isthmus.

Fungi of the genus Candida are found in the air, soil, vegetables, fruits, confectionery. They are representatives of the normal microflora of the intestine, oral mucosa, external genitalia and the area adjacent to natural openings, which are associated with natural reservoirs of fungi of the genus Candida. Thus, about 50% of clinically healthy individuals are carriers of fungi of the genus Candida on the oral mucosa. A small number of yeast cells in the stool (from 100 to 1000 per 1 g of feces) are found in clinically healthy individuals. On other areas of the skin and in the bronchial tract of healthy individuals, they are rarely sown and in small quantities. Other representatives of the normal microflora are in competitive relationships with fungi of the genus Candida.

Pathogenesis of candidiasis

Colonization of the mucous membrane and skin by yeast-like fungi of the genus Candida, as well as manifest candidiasis, is a manifestation of weakened defense of the "host". It has long been known that the most susceptible to this disease caused by opportunistic yeast-like fungi are the very young (infants), the very old or the very sick. Candidiasis is, first of all, a "disease of the sick". Endocrine diseases (hypercorticism, diabetes mellitus, obesity, hypothyroidism and hypoparathyroidism), severe general diseases (lymphoma, leukemia, HIV infection, etc.), pathological pregnancy are among the endocrine factors predisposing to this mycosis. Currently, the most common causes of candidiasis are the use of antibiotics with a broad spectrum of antibacterial action, glucocorticosteroids, cytostatics, hormonal contraception. A number of exogenous factors also contribute to the development of candidiasis. These include elevated temperature and excess humidity, leading to skin maceration, microtrauma, skin damage by chemicals, etc. The simultaneous impact of several predisposing factors (endogenous and exogenous) significantly increases the risk of developing candidiasis. Infection usually occurs in the birth canal, but the possibility of transplacental infection (congenital candidiasis) has also been proven. The occurrence of candidiasis in adults most often occurs as a result of autogenous superinfection, although exogenous superinfection (genital, perigenital areas) may also occur. Dysbacteriosis and disruption of the protective system of the mucous membrane and skin surface facilitate the attachment (adhesion) of the fungus to epithelial cells and its penetration through the epithelial barrier.

Symptoms of Candidiasis

The following types of candidiasis are distinguished:

1. Superficial candidiasis (mouth, genitals, skin, nail folds and nails).
2. Chronic generalized (granulomatous) candidiasis in children and adolescents (chronic mucocutaneous candidiasis).
3. Visceral candidiasis (damage to various internal organs and systems): candidiasis of the pharynx, esophagus and intestines, candidiasis of the bronchi and lungs, candidal septicemia, etc.

Dermatovenerologists and dermatocosmetologists in their daily practice often encounter manifestations of superficial candidiasis. According to the localization of lesions, they distinguish:

1. Candidiasis of the mucous membranes and skin: candidal stomatitis, candidal glossitis, candidiasis of the corners of the mouth (angular cheilitis), candidal cheilitis, candidal vulvovaginitis, candidal balanoposthitis.
2. Candidiasis of the skin and nails: candidiasis of large folds, candidiasis of small folds, candidal paronychia and onychia (onychomycosis).

The most common form of superficial candidiasis of the mucous membranes is candidal stomatitis. The most common clinical form of acute candidal stomatitis is "thrush" or pseudomembranous candidiasis. It often occurs in newborns in the first 2-3 weeks of life and in adults with the predisposing factors listed above. The lesions are usually located on the mucous membrane of the cheeks, palate, and gums. Whitish-cream crumbly plaques appear in these areas. Sometimes they resemble curdled milk and can merge over a significant area into continuous whitish shiny areas. Under them, you can often find a hyperemic, less often eroded surface. With long-standing candidal stomatitis, it acquires a brown-brown or cream color and is more firmly retained on the affected mucous membrane.

Persistent candidal stomatitis and glossitis should be treated by a doctor, as they may be among the first manifestations of acquired immunodeficiency (in HIV-infected individuals).

In patients with lesions of the oral mucosa, mycosis often spreads to the corners of the mouth - candidiasis of the corners of the mouth (yeast, or candidal, angular cheilitis) develops. It can also occur in isolation and usually lasts for a long time. Limited erosions appear in the corners of the mouth - cracks on a slightly infiltrated base, surrounded by a fringe of slightly raised whitened epidermis. The appearance of yeast angular cheilitis is facilitated by maceration of the corners of the mouth, which occurs with malocclusion. The clinical manifestations of candidiasis and streptoderma of the corners of the mouth are similar.

Candidal cheilitis is an inflammation of the red border of the lips. It is characterized by moderate swelling and cyanosis of the red border of the lips, thin grayish lamellar scales with raised edges, thinning of the skin of the lips, radial grooves, cracks. Subjectively, dryness, slight burning, and sometimes pain are disturbing. With macrocheilitis, the lips thicken significantly, thick crusts and bleeding cracks appear on their surface. Similar clinical manifestations occur with atopic cheilitis and streptococcal lesions of the red border of the lips.

Candidal vulvovaginitis is characterized by the formation of a whitish coating (like thrush) on the hyperemic mucous membrane of the vulva and vagina. Characteristic crumbly white discharge appears. Patients are bothered by excruciating itching and burning. The lesion is difficult to treat and is prone to relapse. Yeast vulvovaginitis usually develops with persistent treatment with antibacterial antibiotics, in patients with decompensated diabetes mellitus and pregnant women, with "hidden" infections, and with long-term use of hormonal contraceptives. The disease can be transmitted from wife to husband, who develops yeast balanoposthitis. Candidal urethritis is rare.

Candidal balanoposthitis often occurs against the background of obesity, decompensation of diabetes mellitus, in men with chronic gonorrheal and non-gonorrheal urethritis and in individuals with a narrow foreskin. On the head and inner leaf of the foreskin, against the background of hyperemia, numerous small pustules appear, transforming into erosions of varying sizes with whitish plaque. These manifestations are accompanied by itching and burning. In the absence of adequate therapy, they can lead to inflammatory phimosis, and there is a risk of candidal urethritis.

Candidiasis of large folds (skin under the mammary glands, axillary fossa, inguinal folds, intergluteal fold and abdominal folds) usually develops in obese individuals, in individuals suffering from diabetes mellitus and receiving glucocorticosteroid hormones. In candidiasis of small folds (skin of interdigital folds of the feet and hands) on the hands, most often between the III-IV fingers, as a result of prolonged maceration, interdigital yeast erosion occurs. In large and small folds on hyperemic skin, thin-walled, often merging pustules appear. r further, dark cherry-colored erosions with a shiny, "varnished" surface are formed. The edges of the erosions are polycyclic, with a fringe of peeling white epidermis, raised along the periphery in the form of a "collar". Small pustules (satellite pustules) and erosions are found around the lesion. Characterized by severe itching and burning, differentiation of the disease from streptococcal diaper rash is often difficult.

In individuals with endocrine disorders (usually when several predisposing factors are present), widespread superficial candidiasis of the skin and mucous membranes may occur.

In the presence of a primary focus of candidiasis, allergic rashes may occur - levurides (from the French levures - yeast). They manifest themselves as itchy limited or widespread vesicular, papular or erythematosquamous rashes.

Diagnosis of candidiasis

The presence of yeast-like fungi in the lesions of patients is determined by microscopic and cultural studies. Microscopy of native or aniline-stained preparations for candidiasis reveals a large number of budding cells, pseudomycelium or true mycelium. However, it is necessary to remember that a single finding of single yeast cells in the preparation under study or obtaining single colonies of the Candida fungus during sowing is not proof of the candidal nature of the disease. Of great importance are the corresponding clinical manifestations, quantitative counting of colonies and an increase in their number as the disease progresses.

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Treatment of candidiasis

To prescribe rational treatment for a patient, it is necessary to take into account the clinical form of candidiasis, its prevalence and identified predisposing factors (general and local). In case of superficial candidiasis of the oral mucosa, genitals and perigenital area, it is necessary to determine the degree of contamination of the gastrointestinal tract with Candida yeast. In case of massive colonization of the gastrointestinal tract with Candida fungi, it is advisable to prescribe drugs to suppress their growth (for example, natamycin - Pimafucin).

In case of local lesions of the skin and mucous membranes caused by candidiasis, treatment is usually limited to the external use of anticandidal drugs in rational forms.