Candidiasis, also known as moniliasis , is a condition in which the genus Candida; type of yeasts, grow out of control in moist skin areas of the body. Over 20 species of Candida yeasts produce a wide spectrum of diseases, ranging from superficial mucocutaneous disease to invasive illnesses, where the most common is Candida albicans.

Candidiasis can infect the mouth, vagina, skin, stomach, and urinary tract. The types of candidiasis are classified according to the area they are formed in. Candidiasis that develops in the mouth or throat is called thrush or oropharyngeal candidiasis. Candidiasis in the vagina is commonly referred to as a yeast infection which is also known genital/ vulvovaginal candidiasis when it occurs in both men and women. Invasive candidiasisoccurs when Candida species enter the bloodstream and spread throughout the organs of the body.

An overgrowth of the Candida yeasts that normally reside in the intestinal tract, mucous membranes and skin causes symptoms of candidiasis. Causes of this overgrowth may include taking certain drugs like broad-spectrum antibiotics, corticosteroids, and some birth control pills, pregnancy, or different health conditions that cause any defects among the host defense mechanisms.

The development of candidiasis is specifically linked to host defects. Colonization of the skin and superficial mucosal sites is the first step in the development of candidiasis. Certain virulence factors; they favor the infection process for Candida species  against the host defense, such as surface adhesion molecules that permit the colonization of the organism on the epithelial surfaces.

Signs and symptoms of candidiasis depend upon the site of infection. The most common symptoms in oral thrush and yeast infection are, white patches or plaques in the mouth or throat, and vaginal itching and irritation with a white discharge, respectively. Invasive candidiasis is different from the other two types by being a serious infection that can affect the blood, heart, brain, eyes, bones, and other parts of the body. Candidemia, a bloodstream infection with Candida, is a common infection in hospitalized patients.

A healthcare provider usually makes the diagnosis for candidiasis based on the symptoms, taking a scraping of the affected areas to examine under a microscope, or using a culture that may also be performed, particularly in invasive conditions.

The patient’s age, immune status, location and severity of the infection govern the precise type and dose of the antifungal medication used for treatment. Several different antifungal medications are available to treat candidiasis such as oral antifungal medication, suppositories or creams. Mild or moderate infections can sometimes be treated with a single dose of oral antifungal medication, but some people who may have recurrent or resistant infections usually receive an intravenous antifungal treatment through the vein.

Complication of candidiasis is occasionally a problem for healthy children and adults. However, for people with lowered immunity, for instance from HIV or cancer, candidiasis can be more serious where there is a risk that it will spread into the blood. People who are at high risk for developing candidiasis, can use prescribed antifungal prophylaxis; antifungal medication used to prevent the infection.

Avoiding tight-fitting underwear or pants, avoiding unnecessary antibiotic use, maintaining good hygiene and limiting the amount of sugar in foods consumed may help lower the risk of developing candidiasis.

Candidiasis is a minor condition in healthy people since it effectively treated with medication. On the other hand, untreated or recurrent candidiasis may lead to a more serious form of invasive candidiasis and Candida infections.

According to Centers for Disease Control and Prevention, the oral thrush is not very common in the general population, but is more common in babies less than one month, cancer and AIDS patients. Genital/ vulvovaginal candidiasis is relatively common, where almost 75% of all adult women have had at least one “yeast infection” in their lifetime. Invasive candidiasis is often associated with high rates of morbidity and mortality as well as increased rates in hospitalized patients.

Candidiasis is a fungal infection caused by yeasts that belong to the genus Candida. More than 20 species of Candida yeasts are responsible for human infections but Candida albicans is the prevalent cause of the disease. Candida yeasts are among the normal flora of  the intestinal tract, and do exist on mucous membranes and skin without causing infection. Symptoms do start to appear in the case of an overgrowth of these organisms.. The area of the body that is infected determine the accompanying symptoms of candidiasis. It can infect the mouth, vagina, skin, stomach, and urinary tract.

1. Oropharyngeal / Esophageal  candidiasis

 The fungus Candida albicans builds up on the lining of the mouth and throat, also called oral thrush. It is characterized by white patches or plaques on the tongue and other oral mucous membranes. This type of infection could lead to serious and uncontrollable symptoms in people with an immunocompromised system.  is uncommon among healthy adults, but is predominant in babies, elderly people, people with certain health conditions, or those who take certain medications. Candida overgrowth can also develop in the esophagus, and this is called esophageal candidiasis.

1. Genital / Vulvovaginal Candidiasis

Vulvovaginal candidiasis, also referred to as yeast infection, occurs when there is an overgrowth of the normal yeast; Candida, in the vagina and the vulva; the tissues at the vaginal opening. The usual case for Candida is to exist in the vagina in small amounts. The infection occurs in the case of an imbalance, which is caused by many factors such as a change in the normal acidity of the vagina or when hormonal balance changes. Vaginal yeast is not a sexually transmitted disease, but it can spread through oral-genital sexual contact. On rare occasions, men may also get genital candidiasis.  

1. Invasive candidiasis

Candidemia is a case of bloodstream infection with Candida that is a common infection in hospitalized patients. When Candida infection spreads from a bloodstream to other parts of the body such as heart, kidney, liver and brain, eyes, bones and other parts, it is called invasive candidiasis. This is the most serious of Candida infection.

Candidiasis is caused by an overgrowth of the harmless yeast fungus of the genus Candida ,usually Candida albicans , that normally resides in the mouth, stomach, and vagina. This overgrowth can be caused by many factors such as taking certain drugs like antibiotics, corticosteroids, and some birth control pills, pregnancy, having a bacterial infection, or several different health conditions such as an impaired immune system, diabetes, and psoriasis.

Candidiasis could occur with anyone. However, certain risk factors make it more common in some individuals more than others, including:

• This involves any medication that causes an imbalance in the normal bacteria found in the body, such as antibiotics, oral or inhaled corticosteroids, in addition to broad-spectrum antibiotics, which suppress the bacterial flora that are normally present in the body along with pathogenic bacteria. For example, the natural role for the Lactobacillus bacteria is to produce acid, which prevents yeast overgrowth. This is disturbed by some medications which decrease the vaginal lactobacillus bacteria, change the pH; a measure of acidity and alkalinity of a solution, of the vagina and lead to a yeast infection.

• Patients with uncontrolled or untreated diabetes mellitus could have their saliva containing large amounts of sugar, which promotes the growth of Candida.

• Weakened immune systems increase the possibility of opportunistic infections, which can be found in infants or the elderly, people who have had an organ transplant or have an HIV infection, and patients who undergo chemotherapy or radiation treatment for cancer.

• At the hospital, being recently admitted especially the intensive care unit (ICU)  or if a central venous catheter was used or, having surgery, particularly gastrointestinal surgery , all could increase the risk for candidiasis.  

• High estrogen levels ; a hormone that control the reproductive system ,  make yeast infections more common in women such as in pregnant women, women who are on high-dose estrogen birth control pills or estrogen hormone therapy.

•  People who have conditions that cause a dry mouth or using dentures.
• Sexual contact can be responsible for spreading Candida. Yeast infection is not a sexually transmitted disease, but it can spread through oral-genital sexual contact.

Candida infections of the skin and superficial mucosal sites are the result of an interaction between fungal virulence and host defenses. The expression of epidermal proliferation and T-lymphocyte immune responses, and to some extent that of the inflammatory responses and nonspecific inhibitors by the host is necessary to fight fungal invasion. A defect in the host, is a major participant in the development of candidiasis, similar to any type of fungal infection. Defects in the defense mechanisms of the host against Candida infections are usually related to many reasons, including having weakened immune systems such as HIV infections, granulocytopenia which is a lower than normal number of granulocytes (type of white blood cells)

, and myeloperoxidase deficiency which is the lack of a human enzyme located in the neutrophils that contributes to killing microbes

, patients who have taken chemotherapy or radiation treatment for cancer, and people using broad spectrum antibiotics.

A set of virulence factors define the extent to which Candida species are able to cause an infection which are, surface adhesion molecules that make it feasible for the organism to attach to the epithelial surfaces. Enzymes such as acid proteases and phospholipases that facilitate penetration and damage of cell envelopes, and the ability to convert to a hyphal form; elongated tubular structures in fungi , which permit penetration to a deeper area.

Candidiasis follows a series of events in order to develop an infection. The infection begins with colonization of the skin and superficial mucosal sites and causing it to break,  which can be followed by organisms to enter the bloodstream which is called candidemia.  Further spread of candidemia to other parts of the body such as heart, kidney, liver and brain, eyes, bones and other parts, is called invasive candidiasis.

1. Symptoms of Oropharyngeal / Esophageal candidiasis

Depending on the cause, signs and symptoms may develop slowly or suddenly, and they may even last for days, weeks or months. Symptoms included :

• White patches or plaques on the tongue and other oral mucous membranes are the most frequent among oral thrush symptoms.
• Slightly raised lesions with a cottage cheese-like appearance.
• Redness or soreness so severe that they cause difficulty eating or swallowing.
• Lesions could have slight bleeding when they are rubbed or scraped.
• Cracking and redness at the corners of your mouth called angular cheilitis, especially in people who wear dentures.
• A cottony feeling in your mouth.
• Loss of taste.
• Candida esophagitis is seen as candidiasis that cause difficulty in swallowing or feeling as if food is being stuck in the throat.

Infants may face problems such as trouble feeding or being irritable, in addition to white mouth lesions. Infection is spread from the infant to the mother and alternatively returned to the infant, during breastfeeding. Women whose breasts are infected with Candida may experience these signs and symptoms:

• Unusually red, sensitive, or itchy nipples.
• The areola; the circular area around the nipple could become shiny or flaky skin.
• While nursing, the process itself could be unusually painful, in addition to sensing painful nipples between feedings.
• Stabbing pains deep within the breast.

1. Symptoms of  yeast infection

Mild to moderate symptoms could accompany yeast infections, including:

• Itching and irritation in the vagina and the tissues at the vaginal opening (vulva).
• A burning sensation, especially during intercourse or urination.
• Redness and swelling of the vulva.
• Vaginal pain and soreness.
• Vaginal rash.
• Watery vaginal discharge.
• Thick, white, odor-free vaginal discharge with a cottage cheese appearance.
• Men with genital candidiasis may experience an itchy rash on the penis.

1. Symptoms of invasive candidiasis

Symptoms of invasive candidiasis vary depending on the body part involved in the infection. However, the most common symptoms of invasive candidiasis include headache, fever, nausea and chills.

Each case of candidiasis has certain diagnosis tools as follows:

• Oral thrush

1. Detecting the infection by directly looking at the lesions.
2. Taking a small scraping of the affected areas to examine under a microscope to confirm the diagnosis.
3. To conduct a physical exam and certain blood tests for patients who have no identified risk factors, in order to find out the source of the problem.

If the thrush spreads to the esophagus, a healthcare provider may recommend doing one or both of these tests:

1. Throat culture

 A throat swap from the back of the throat is cultured on a special medium to help determine which bacteria or fungi, if any, are causing the symptoms.

1. Endoscopic exam

 Using a lighted, flexible tube with a camera on the tip called endoscope, the doctor examines the esophagus, stomach and upper part of your small intestine.

• Yeast infection

1. To gather information about the medical history such as information about past vaginal infections or sexually transmitted infections.
2. To perform a pelvic exam that examines the external genitals, followed by examining the vagina, and cervix for signs of infection.
3.  A sample of vaginal secretions is tested under a microscope to see if an overgrowth of Candida is present , in addition to the type of the yeast that is causing the infection.

• Invasive candidiasis

1. The medical history.
2. Symptoms.
3. Physical examinations.
4. Laboratory tests, where the common method used is candidiasis is a blood sample that is sent to a laboratory in order to see whether Candida grows in a culture.

The type and duration of treatment depends on the severity, causes and location of the infection, in addition to  the specific case of the patient such as age and immune status. Recurring infections can be prevented  by eliminating the underlying causes. The goal of any treatment is to stop the rapid spread of the fungus. Therefore, untreated infections can lead to a more serious form of invasive candidiasis. Treatment divides into:

Oropharyngeal / Esophageal candidiasis

•  Antifungal medication that are available as lozenges, tablets such as fluconazole or itraconazole, or a suspension like nystatin. In some cases, Candida albicans could become resistant to antifungal medications, especially in people with a late-stage HIV infection which demands an intravenous medication, amphotericin B.  Infants and breast-feeding mothers should both take suitable medications that stop the alternation of the infection. A mild antifungal medication is usually prescribed for baby and an antifungal cream for the mother’s breasts.

• Esophageal candidiasisis typically treated with oral or intravenous medications such as fluconazole. Severe cases of esophageal candidiasis require treatment with amphotericin B.

Genital / vulvovaginal candidiasis

Several types of antifungal medications are available to treat genital / vulvovaginal candidiasis. Symptom severity is the guide for course duration and dose.

• Mild or moderate infections and infrequent episodes of yeast infections can be treated by short courses of vaginal therapy, which are available as creams, ointments, tablets and suppositories. Some of these medications are available by prescription only, while others are available as over-the-counter, including butoconazole, clotrimazole, and terconazole. Single doses of fluconazole oral medication or even two single doses in severe cases, might be taken by mouth instead of vaginal therapy.
• Complicated, recurrent or resistant yeast infections can be treated by long courses of vaginal therapy, which are available as creams, ointments, tablets or suppositories. Multidose of fluconazole oral medication might be taken by mouth instead of vaginal therapy, with the exception of pregnant women. Recurrent infections should have a maintenance plan which involves treating the infection, followed by a medication routine.

Invasive candidiasis

• The source of infection should be determined and if possible, removed. Unlike thrush or vaginal Candida infections, invasive candidiasis is a medical emergency that requires immediate admission to an intensive care unit. The specific type and dose of the antifungal medication depends usually on the age and immune status of the patient, in addition to the location and severity of the infection. For most adults, the initial recommended antifungal treatment is an echinocandin given intravenously. Fluconazole, amphotericin B, and other antifungal medications may also be appropriate in certain situations.

Complication of oral thrush

In healthy children and adults, oral thrush rarely causes complications. However, untreated oral thrush can lead to more-serious invasive candida infections. In people who are immunosuppressed due to HIV or cancer, the infection may:

• Spread to other parts of the body, such as lungs, liver and heart valves.
• Cause severe symptoms in the mouth or esophagus, which makes swallowing painful and difficult.
• Spread to the intestines, making it difficult to receive adequate nutrition.

1. Complication of yeast infection

The following conditions increase the risk of a complicated yeast infection:

• Severe symptoms, such as the widespread of redness, swelling and itching that leads to sores.
• Recurrent yeast infections, four or more times in a year.
• Infections that are not caused by Candida albicans but rather other species.
• Pregnancy.
• Uncontrolled diabetes mellitus.
• A suppressed immune system because of certain medications or conditions such as HIV infection.

Invasive candidiasis is most likely to occur in patients with  a suppressed immune system, where the risk of the fungus spreading from the oral, esophagus and vagina to blood is increased to later on spread quickly throughout  the organs of the body. Invasive candidiasis begins with candidema; the presence of Candida species in the blood.

 Oral thrush prevention

These procedures may help reduce the risk of developing oral thrush:

• When corticosteroid inhalers are used, it is recommended to wash the mouth with water or mouthwash.
• Brushing the teeth twice a day or more and using floss should be done on a daily basis.
• Dentures should be removed at night and cleaned in the correct way recommended by the doctor, in addition to making sure that they fit in properly and cause no irritation.
• Regular visits to the dentist, especially when having diabetes or wearing dentures.
• Limiting the amount of sugar in foods eaten as sugar may cause the growth of candida.
• Controlling the level of blood sugar in diabetes reduces the amount of sugar in the saliva, which inhibits the growth of candida.
• The condition of a dry mouth should be avoided or treated.

1.  Yeast infections prevention

The following actions can help reduce your risk of vaginal yeast infections including:

• Wearing cotton underwear and loose pants or skirts, in addition to avoiding tight-fitting underwear or pantyhose.
• Wet clothes should be changed quickly such as swimsuits or workout clothes.
• Staying out of hot tubs and very hot baths.
• Antibiotics should only be used when necessary and should be avoided in cases such as colds or other viral infections.
• Recurrent infections may require using oral or intravaginal probiotics to help prevent such infections.
• Treatment of vaginal yeast infections should be immediate.

1. Invasive candidiasis prevention

• Using antifungal prophylaxis; antifungal medication used to prevent the infection, are beneficial to patients who have been solid organ transplant recipients, high-risk ICU patients, and patients with neutropenia; an abnormal low level of neutrophils, that is caused by chemotherapy or being stem cell transplant recipients.

• Following hand hygiene recommendations.
•  Placement and maintenance of central venous catheters should be done according to directions recommended, including the length of time a central venous catheter is needed, and if so, the period of time is needed for the catheter to stay in place.

 Oral thrush in healthy people does not form a major health issue, but the symptoms are quite the opposite in individuals with HIV infections or other immunosuppressed states and could be more severe and difficult to control. An effective treatment with short courses or longer treatment courses for recurrent infections are needed and are very effective in treating yeast infections.

Untreated oral or yeast infections can lead to a more serious form, which is known as invasive candidiasis.

According to Centers for Disease Control and Prevention, oral thrush is not very common in the general population. An estimate between 5% and 7% of babies less than one month old will develop oral candidiasis. The prevalence of oral candidiasis among cancer patients is nearly 20% and in patients with AIDS is estimated to be between 9% and 31%. While genital/ vulvovaginal candidiasis is relatively common, with an incidence of about 75% of all adult women one of having at least one “yeast infection” in their lifetime. On rare occasions, men may also get genital candidiasis. People with suppressed immune systems have frequent or more severe cases of yeast infections.. Invasive candidiasis is linked to high rates of morbidity and mortality, in addition to an increased cost and length when hospitalized. It is estimated that approximately 46,000 cases of healthcare-associated invasive candidiasis occur each year in the US. Candidemia, the most common form of invasive candidiasis, is one of the most common bloodstream infections in the United States.