Candidiasis
Candidiasis is a fungal infection due to any species of the genus Candida. When it affects the mouth or vagina it is commonly known as thrush. Signs and symptoms include white patches on the tongue or other areas of the mouth and throat. Other symptoms may include soreness and problems swallowing. When it affects the vagina, it may be referred to as a yeast infection or thrush. Signs and symptoms include genital itching, burning, and sometimes a white "cottage cheese-like" discharge from the vagina. Yeast infections of the penis are less common and typically present with an itchy rash. Very rarely, yeast infections may become invasive, spreading to other parts of the body. This may result in fevers, among other symptoms. Finally, candidiasis of the esophagus is an important risk factor for contracting esophageal cancer in individuals with achalasia.
More than 20 types of Candida may cause infection with Candida albicans being the most common. Infections of the mouth are most common among children less than one month old, the elderly, and those with weak immune systems. Conditions that result in a weak immune system include HIV/AIDS, the medications used after organ transplantation, diabetes, and the use of corticosteroids. Other risk factors include during breastfeeding, following antibiotic therapy, and the wearing of dentures. Vaginal infections occur more commonly during pregnancy, in those with weak immune systems, and following antibiotic therapy. Individuals at risk for invasive candidiasis include low birth weight babies, people recovering from surgery, people admitted to intensive care units, and those with an otherwise compromised immune system.
Efforts to prevent infections of the mouth include the use of chlorhexidine mouthwash in those with poor immune function and washing out the mouth following the use of inhaled steroids. Little evidence supports probiotics for either prevention or treatment, even among those with frequent vaginal infections. For infections of the mouth, treatment with topical clotrimazole or nystatin is usually effective. Oral or intravenous fluconazole, itraconazole, or amphotericin B may be used if these do not work. A number of topical antifungal medications may be used for vaginal infections, including clotrimazole. In those with widespread disease, an echinocandin such as caspofungin or micafungin is used. A number of weeks of intravenous amphotericin B may be used as an alternative. In certain groups at very high risk, antifungal medications may be used preventively, and concomitantly with medications known to precipitate infections.
Infections of the mouth occur in about 6% of babies less than a month old. About 20% of those receiving chemotherapy for cancer and 20% of those with AIDS also develop the disease. About three-quarters of women have at least one yeast infection at some time during their lives. Widespread disease is rare except in those who have risk factors.
Signs and symptoms
Signs and symptoms of candidiasis vary depending on the area affected. Most candidal infections result in minimal complications such as redness, itching, and discomfort, though complications may be severe or even fatal if left untreated in certain populations. In healthy persons, candidiasis is usually a localized infection of the skin, fingernails or toenails, or mucosal membranes, including the oral cavity and pharynx, esophagus, and the sex organs ; less commonly in healthy individuals, the gastrointestinal tract, urinary tract, and respiratory tract are sites of candida infection.In immunocompromised individuals, Candida infections in the esophagus occur more frequently than in healthy individuals and have a higher potential of becoming systemic, causing a much more serious condition, a fungemia called candidemia. Symptoms of esophageal candidiasis include difficulty swallowing, painful swallowing, abdominal pain, nausea, and vomiting.
Mouth
Infection in the mouth is characterized by white discolorations in the tongue, around the mouth, and in the throat. Irritation may also occur, causing discomfort when swallowing.Thrush is commonly seen in infants. It is not considered abnormal in infants unless it lasts longer than a few weeks.
Genitals
Infection of the vagina or vulva may cause severe itching, burning, soreness, irritation, and a whitish or whitish-gray cottage cheese-like discharge. Symptoms of infection of the male genitalia include red skin around the head of the penis, swelling, irritation, itchiness and soreness of the head of the penis, thick, lumpy discharge under the foreskin, unpleasant odour, difficulty retracting the foreskin, and pain when passing urine or during sex.Skin
Signs and symptoms of candidiasis in the skin include itching, irritation, and chafing or broken skin.Invasive infection
Common symptoms of gastrointestinal candidiasis in healthy individuals are anal itching, belching, bloating, indigestion, nausea, diarrhea, gas, intestinal cramps, vomiting, and gastric ulcers. Perianal candidiasis can cause anal itching; the lesion can be red, papular, or ulcerative in appearance, and it is not considered to be a sexually transmitted infection. Abnormal proliferation of the candida in the gut may lead to dysbiosis. While it is not yet clear, this alteration may be the source of symptoms generally described as irritable bowel syndrome, and other gastrointestinal diseases.Neurological symptoms
Systemic candidiasis can affect the central nervous system, causing a variety of neurological symptoms, with a presentation similar to meningitis.Causes
Candida yeasts are generally present in healthy humans, frequently part of the human body's normal oral and intestinal flora, and particularly on the skin; however, their growth is normally limited by the human immune system and by competition of other microorganisms, such as bacteria occupying the same locations in the human body.Candida requires moisture for growth, notably on the skin. For example, wearing wet swimwear for long periods of time is believed to be a risk factor. Candida can also cause diaper rashes in babies. In extreme cases, superficial infections of the skin or mucous membranes may enter the bloodstream and cause systemic Candida infections.
Factors that increase the risk of candidiasis include HIV/AIDS, mononucleosis, cancer treatments, steroids, stress, antibiotic therapy, diabetes, and nutrient deficiency. Hormone replacement therapy and infertility treatments may also be predisposing factors. Use of inhaled corticosteroids increases risk of candidiasis of the mouth. Inhaled corticosteroids with other risk factors such as antibiotics, oral glucocorticoids, not rinsing mouth after use of inhaled corticosteroids or high dose of inhaled corticosteroids put people at even higher risk. Treatment with antibiotics can lead to eliminating the yeast's natural competitors for resources in the oral and intestinal flora, thereby increasing the severity of the condition. A weakened or undeveloped immune system or metabolic illnesses are significant predisposing factors of candidiasis. Almost 15% of people with weakened immune systems develop a systemic illness caused by Candida species. Diets high in simple carbohydrates have been found to affect rates of oral candidiases.
C. albicans was isolated from the vaginas of 19% of apparently healthy women, i.e., those who experienced few or no symptoms of infection. External use of detergents or douches or internal disturbances 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. Pregnancy and the use of oral contraceptives have been reported as risk factors. Diabetes mellitus and the use of antibiotics are also linked to increased rates of yeast infections.
In penile candidiasis, the causes include sexual intercourse with an infected individual, low immunity, antibiotics, and diabetes. Male genital yeast infections are less common, but a yeast infection on the penis caused by direct contact via sexual intercourse with an infected partner is not uncommon.
Breastfeeding mothers may develop candidiasis on and around the nipple due to the moisture created by excessive milk production.
Vaginal candidiasis can cause congenital candidiasis in newborns.
Diagnosis
In oral candidiasis, simply inspecting the person's mouth for white patches and irritation may make the diagnosis. A sample of the infected area may also be taken to determine what organism is causing the infection.Symptoms of vaginal candidiasis are also present in the more common bacterial vaginosis; aerobic vaginitis is distinct and should be excluded in the differential diagnosis. In a 2002 study, only 33% of women who were self-treating for a yeast infection were found to have such an infection, while most had either bacterial vaginosis or a mixed-type infection.
Diagnosis of a yeast infection is confirmed either via microscopic examination or 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 solution is then added to the specimen. The KOH dissolves the skin cells, but leaves the Candida cells intact, permitting visualization of pseudohyphae and budding 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, allowing development of yeast or bacterial colonies. The characteristics of the colonies may allow initial diagnosis of the organism causing disease symptoms.
Respiratory, gastrointestinal, and esophageal candidiasis require an endoscopy to diagnose. For gastrointestinal candidiasis, it is necessary to obtain a 3–5 milliliter sample of fluid from the duodenum for fungal culture. The diagnosis of gastrointestinal candidiasis is based upon the culture containing exceeding 1,000 colony-forming units per milliliter.