Candidiasis, also known as "Candida" or "yeast", is an infection caused by strains of Candida fungi, especially Candida albicans. Candida normally lives harmlessly in the body, but under certain conditions it may multiply out of control. Candida can affect different parts of the body, causing either localised infections or overwhelming illness, depending on the individual's general state of health.
Types of Candida infection
Candida infection is named according to the area of the body in which it occurs. The following are some of the body sites where candida may be present:
- Vaginal yeast infection or candida vaginitis
Yeast infection of the vaginal area is common. If the infection is also present at the vulva (the area around the entrance to the vagina), the condition is known as vulvovaginal candidiasis. The infection commonly occurs as a result of self contamination with yeast organisms from the rectal passage. Sexual transmission is possible but unusual. Vaginal candida infections are not usually transmitted sexually. They are often included among the sexually transmitted diseases because they may occur with other types of reproductive system infections.
- Oral thrush
This is a superficial, sometimes recurrent infection that affects moist surfaces around the lips, inside the cheeks and on the tongue and palate. Oral thrush is generally not contagious.
- Oesophageal thrush (Oesophagitis)
Oral thrush can spread to the oesophagus which is the connecting passage between the mouth and the stomach.
- Cutaneous (skin) candidiasis
Candida can cause infections in areas of skin that are moist and receive insufficient ventilation. Some common sites include the nappy/diaper area ("nappy rash" or candidal dermatitis) in babies; the webs of fingers and toes; the groin and the crease of the buttocks; the skin under large breasts; and the fingernail beds.
A less common but equally irritating infection on the glans of the penis and beneath the foreskin.
- Systemic candidiasis
A condition which only affects people with compromised immune systems, for example, those who are HIV-positive, have cancer or are on immune suppressive drugs after organ transplantation. Candida fungi contaminate the bloodstream and spread throughout the body, causing severe infection. Typical organs that can be affected include the brain, eyes, liver and heart.
Causes of Candida Infection
Candidiasis is caused by overgrowth of the candida fungi that can occur in the body. Candida fungi usually live harmlessly along with the "friendly" species of bacteria that normally colonise the mouth and gastrointestinal andurogenital tracts.
In a healthy person, the growth of candida is kept in check by a properly functioning immune system and the presence of friendly bacteria.
However, certain internal and external factors can change the normal environment and trigger an overgrowth of the yeast. Candida fungi can multiply out of control if the numbers of friendly bacteria are reduced, the immune system is weakened, or other conditions for yeast proliferation occur.
When fungal growth at a certain body site exceeds the body's ability to control it, yeast infection develops.
Risk factors for Thrush
The following are factors that can predispose you to candida overgrowth:
- Antibiotics can reduce the number of friendly intestinal bacteria which normally help to keep candida under control. Up to one-third of women are susceptible to vulvovaginal candidiasis during or after taking broad spectrum antibiotics. Taking probiotics such as lactobacilli (oral or vaginal) at the same time as antibiotics does not prevent post antibiotic vulvovaginitis.
- Medications such as steroid hormones, immunosuppressant and anti-inflammatory drugs, chemotherapy drugs and ulcer medications or acid blockers used for prolonged periods.
- Immune deficiency. Diseases such as AIDS and cancer can weaken the immune system. The immune system can also become weaker in the elderly.
- Diabetics are prone to yeast infections, especially when their blood sugar levels are not well controlled. High levels of sugar in the blood and urine, and a low resistance to infection are conditions that encourage yeast growth.
- Certain genetic disorders, such as celiac disease (which involves intestinal malabsorption) or haemochromatosis (in which iron accumulates in body tissue).
- Hormonal imbalance, as a result of menstruation, pregnancy, diabetes or birth control pills (usually in the first three months of taking them) or thyroid disease. Vulvovaginal candidiasis appears to be linked to increased oestrogen levels.
- During their lifetimes, about 75 percent of all women are likely to have at least one vaginal candida infection before they reach menopause, and up to 45 percent will have two or more. Women tend to be more susceptible to vaginal yeast infections if they are under stress, have an inadequate diet, have lack of sleep or are ill. Although it is not classified as a sexually transmitted disease, yeast infections are common among younger women (ages 20 to 40), especially after becoming sexually active.
- If a woman has a vaginal yeast infection when she gives birth, the baby may get yeast (thrush) in its throat or digestive tract.
- When the balance between commensal (friendly) and pathogenic (disease-causing) bacteria in the normal intestinal flora is disturbed, for example due to excessive alcohol consumption and certain chemicals.
- A moist, warm environment. Yeast infections often develop where a moist, warm environment encourages fungal growth. Prime areas include the webs of fingers and toes, nails, genitals and folds of skin. This is particularly the case in diabetics.
- Tight clothing, especially underwear that promotes moisture build-up.
- Being obese (over 20 percent overweight).
- Thrush is a common minor infection in babies and young children.
- People, whose work requires that they spend long periods of time with their hands in water, or who wear rubber gloves, are predisposed to cutaneous candidiasis.
- Candida in the male genital area (balanitis) has been found to be more common in uncircumcised males or diabetics, and can sometimes result from intercourse with an infected partner.
- In rare cases, the candida fungus may invade the body at certain sites: intravenous (IV) tube, urinary catheter, tracheostomy, ventilation tubing or surgical wounds. If the infection spreads through the bloodstream to the kidneys, lungs, brain or other organs, it can cause serious systemic complications. These develop only in people who are seriously ill or who have other health problems that weaken the immune system.
Symptoms and signs of Candidiasis
Candidiasis produces different symptoms, depending on the type of tissue infected:
- Oral thrush causes curd-like, usually painless, white patches inside the mouth, especially on the tongue and palate and around the lips. These patches may come off when eating or when brushing the teeth. When scraping off the whitish surface of a patch, a red and inflamed area, which may bleed slightly, will become visible. The corners of the mouth may also be cracked, red and sore. The fungus can also cause creamy-yellow, raised sores on the mouth.
- Oesophageal thrush may make swallowing difficult or painful, and may sometimes cause chest pain.
- Cutaneous candidiasis causes patches of itchy (sometimes painful) red, moist, weepy skin with small red bumps or pustules. Other symptoms include peeling skin, especially between the fingers, and swollen nail folds above the cuticle.
- Vaginal yeast infections may cause the following symptoms:
- Vaginal itching and/or soreness
- A thick, white discharge which may resemble cottage cheese and smell like baking bread
- Burning discomfort around the vaginal opening, especially when urinating
- Pain or discomfort during sexual intercourse
- Redness and swelling of the vulva
- Some women infected with Candida have no symptoms
- Balanitis: red patches, swelling and blisters typically occur on the glans (tip) of the penis and foreskin, possibly accompanied by itching and burning
- Systemic candidiasis: when candida spreads through the bloodstream, it may cause a wide range of symptoms, from unexplained fever to shock and multiple organ failure.
The doctor will take a detailed medical history and will also ask about recent use of medications that could suppress the immune system. If the doctor suspects cutaneous candidiasis, questions will be asked about skin care and about conditions that could expose the skin to excessive moisture, such as wearing overly tight clothing or rubber gloves.
Thrush, cutaneous candidiasis or vaginal yeast infection can often be diagnosed by a simple physical examination and viewing a scraping sample through a microscope at the doctor's office. However, if the diagnosis is in question, the doctor may send a sample of skin scrapings or vaginal discharge to the laboratory for testing. To diagnose oesophageal thrush, the doctor will use an endoscope, a flexible instrument that is passed into the oesophagus to allow direct examination of the area. During this procedure, called endoscopy, a sample will be taken from the oesophagus to be examined in the laboratory.
If the doctor suspects an underlying medical condition that increases the risk for candidiasis — such as diabetes, cancer or HIV infection — blood tests or other types of diagnostic procedures may be necessary.
You can help to prevent candida infections by:
- Keeping the skin clean, cool and dry
- Avoiding frequent or prolonged use of oral antibiotics if possible
- Losing weight if obese
- Keeping blood sugar levels as normal as possible if suffering from diabetes
- Wearing rubber gloves if your work involves keeping hands in water for long periods. Each time the gloves are removed, the hands should be washed and dried. Applying a mild, over-the-counter antifungal cream may be of additional benefit.
- To help prevent vaginal yeast infections:
- The skin of the vulva and anus should be washed regularly and kept dry after bathing. Other people's towels or washcloths should not be used.
- The use of chemical products such as bubble bath, hygiene spray, irritating soaps, perfumes or talcum powder should be avoided or kept to a minimum.
- Dry cotton or silk underclothes allow better airing and evaporation of excess moisture, compared to synthetics. Any tight-fitting garments should be avoided, particularly when exercising.
- Vaginal douching should be avoided. The vagina does not require cleansing other than normal bathing. Repetitive douching disrupts the balance of normal organisms that live in the vagina and can actually increase the risk of vaginal infection.
- If a genital candida infection is present, a condom should be used during sexual intercourse. Although uncommon, candida organisms can also be transmitted through kissing and orogenital contact.
For people with HIV who are at risk of recurrent episodes of thrush, doctors sometimes prescribe antifungal drugs as a preventative measure.
After having made the diagnosis, the doctor will prescribe the necessary medication. Treatment of candidiasis aims to curb the growth of the organism that causes the infection. It depends on the area affected, the severity of the infection and whether it is a first-time or recurrent infection. Antifungal drugs resolve most cases of common yeast infection.
- Oral thrush is usually treated with antifungal medications such as nystatin or clotrimazole. For mild cases, a suspension of nystatin can be swished in the mouth and swallowed, or a clotrimazole lozenge dissolved in the mouth. For more severe cases, itraconazole or fluconazole may be taken which are systemic antifungals, meaning that they are absorbed through the intestine and then reach the target via the bloodstream.
- Oesophageal thrush is usually treated with itraconazole or fluconazole.
- Cutaneous candidiasis can be effectively treated with a variety of topical antifungal drugs such as powders, lotions and creams. The affected area must be kept clean and dry and protected from chafing.
- Vaginal yeast infections can be treated with topical antifungal medications administered directly into the vagina as creams, ointments or suppositories. These medications include nystatin and so-called imidazole derivatives (clotrimazole, econazole, fenticonazole, ketoconazole, tioconazole, terconazole and miconazole.) Oral antifungals are often easier to use but take a day or two longer to relieve symptoms than topical agents. Patients with recurrent infections or are complicated by diabetes or immune suppression may require up to two weeks of topical therapy or are often treated with systemic antifungals. While taking antifungal medications:
- Complete the full treatment even if you start feeling better.
- Continue the course of treatment if you are menstruating.
- Do not douche.
- Avoid sexual intercourse when there is active infection.
- To ease discomfort, try applying a cold compress, such as a wash cloth, to the labial area several times a day. Ask your doctor or pharmacist to recommend an anti-itch medication.
- After urinating, wipe gently to avoid irritation.
- It may take a week or more for inflammation and burning to subside even though the infection has been properly treated.
- Balanitis: In addition to practising good hygiene, antifungal medications may be required to clear the infection. If the problem is a recurrent one, adult circumcision may be an option.
- Systemic candidiasis requires intravenous treatment at a hospital.
In most otherwise-healthy individuals with superficial candidiasis, the infection can be treated without leaving permanent damage. It is unlikely to return as long as the person remains healthy and well-nourished.
However, in people with weakened immune systems, candida infections can be difficult to treat and may recur. In these cases, candidiasis can sometimes be life-threatening if it passes into the blood and spreads to vital organs like the lungs, kidney, heart and brain, where it can be fatal.
People with severely compromised immune systems can die from a form of blood poisoning known as candidasepticaemia. Cases of systemic candidiasis that are diagnosed quickly and treated effectively have the best prognosis, especially if the infection can be stopped before it spreads to major organs.
There have been several home remedies described, such as applying plain yoghurt to the vulva or directly into the vagina, or drinking unsweetened cranberry juice to curb candida overgrowth. Some women may find them helpful in relieving part of the discomfort associated with candidiasis. However, the disadvantage as with any self medication is that the diagnosis is not made by a medical professional. A woman suffering from an itchy discharge may have a candida vulvovaginitis and a STD simultaneously and, by delaying a proper examination with the correct diagnosis and necessary treatment, the condition may become worse. Studies have found that self-diagnosis of vulvovaginal candidiasis is frequently inaccurate, and therefore it is best to consult a doctor.
When to see a doctor
A woman should be attended by a doctor if she experiences symptoms of a candida infection and:
- It is the first time that she has such symptoms
- The infection does not respond to the prescribed treatment or recurs within a two-month period
- She suffers from a chronic illness or weakened immune system, or is taking medication to suppress the immune system
- She is pregnant. Oral antifungal medications are contraindicated during pregnancy.
Reviewed by Prof B. Schaetzing MD, FCOG (SA), FRCOG, PhD. Part-time Consultant, Dept of Obstetrics & Gynaecology, Faculty of Health Sciences, University of Stellenbosch
Updated by Dr Judith Kluge,MB ChB, FCOG (SA), MRCOG. Dept of Obstetrics & Gynaecology, Tygerberg Academic Hospital, University of Stellenbosch, December 2010