Candidiasis, also called thrush or moniliasis, is a yeast infection. Candida albicans is an organism that normally makes a quiet home for itself on your skin and doesn't bother anyone. We all carry this organism on our skin, in our mouth, in our gastrointestinal tract (gut), and, in the case of women, in the vagina.
Occasionally the yeast multiplies uncontrollably, causing pain and inflammation. Candidiasis may affect the skin. This includes the external surface skin and the skin of the vagina, the penis, and the mouth. Candidiasis may also infect the blood stream or internal organs such as the liver or spleen. By far the most common problems are skin, mouth and vaginal infections. It also is a common cause of diaper rash. These can be bothersome infections, but are not life threatening.
Candidiasis can kill if it reaches the bloodstream or vital organs such as the heart, but this is rare even in people with damaged immune systems and is almost unheard of in healthy people. Nevertheless, candidiasis is a constant nuisance, and sometimes a serious threat to people with AIDS and some cancer patients who lack the immune resources to fight it.
You don't catch candidiasis. The yeast is already there. A number of factors can increase the chance of the yeast growing out of control. The leading cause is overuse of antibiotics. Yeast must compete for the right to live on us with various other organisms, many of them bacteria. These bacteria, which live on the skin and in the intestine and vagina, among other places, are harmless but good at fighting off yeast. When we take antibiotics to deal with less friendly bacteria, we kill off these harmless ones as well. Yeast, which is unaffected by antibiotics, moves into the vacated spots once occupied by bacteria, and starts to grow and multiply.
Steroids and some cancer medications weaken the immune system and can allow yeast to flourish. Candida albicans infections of the mouth (known as oral thrush) most often develop in people with diseases such as cancer and AIDS. They can also develop in people with diabetes or in people who have long-term irritation resulting from dentures. Taking birth control pills increases your chances of getting vaginal candidiasis. Hot weather and tight clothing are also risk factors, as they create the ideal environment for candida.
Other conditions that tend to encourage yeast include obesity and pregnancy. Yeast generally infects intertriginous areas, that is, areas where skin contacts skin. Overweight people have more folds in their skin. They also sweat more, and Candida albicans is fond of moist skin. Pregnancy causes temporary obesity and may weaken the immune system, increasing the risk of yeast infections.
Experts disagree on the question of sexual transmission. Some research has suggested that it's very unlikely for an infected woman to give a man candidiasis. On the other hand, it's not unlikely that a man could give candidiasis back to his partner once he has it. Recent research has actually found Candida albicans in the sperm of men whose partners suffered from recurrent yeast infections. You should be aware of this possibility if a yeast infection keeps coming back.
Symptoms and Complications
A candida infection of the skin appears as a clearly defined patch of red, itchy skin, often leaking fluid. Scabs and pustules may be seen around the edge of the rash. It will usually be found in areas such as the groin, the folds of the buttocks, between the breasts, toes, or fingers, and in the navel.
A vaginal yeast infection may well result in a slow leakage of a thick, white, cheese-like substance. The vagina may itch or burn, especially during urination or sex. Pain or discomfort during intercourse is common.
Candidal paronychia is candidiasis of the fingernails. It often strikes people whose hands are in water a lot. Sometimes it presents as a painful, red, swollen area around the fingernail. In worse cases, the fingernail may separate, revealing a discoloured white or yellow nail bed.
Oral thrush causes curd-like white patches inside the mouth, on the tongue and palate and around the lips. It may also cause cracked, red, moist areas of skin at the corners of the mouth. Thrush patches may or may not be painful.
Yeast infections of the penis are rare but may cause the tip to be red, swollen, and painful.
Making the Diagnosis
To make a diagnosis your doctor will ask about your diet and recent use of antibiotics or medications that can weaken the immune system. The doctor will also take into consideration any history of diabetes, cancer, HIV, or other chronic diseases.
Candidiasis is easy to identify. The yeast can be seen under the microscope after being scraped off the affected area. However, since yeast is normally there anyway, your doctor will want to be sure that it's candida causing the problem and not something else. The appearance of the rash may be enough.
Treatment and Prevention
Candidiasis isn't normally a dangerous disease except in rare cases when it enters the blood and spreads to vital organs of people with weakened immune systems.
For infection of the skin, your doctor can give you an antifungal cream or powder or prescribe you an antifungal pill. For vaginal yeast infections, treatment consists of antifungal medications that are administered directly into the vagina as tablets, creams, ointments, or suppositories, or administered by mouth (e.g., fluconazole*). For oral thrush, a suspension of antifungal medication can be swished in the mouth and swallowed, or sometimes the doctor will have you dissolve an antifungal lozenge in the mouth.
For severe cases, antifungal medication taken by mouth for several days may be needed. Speak with your pharmacist - you can buy many of the creams and powder products intended for minor infections without a prescription.
Here are some hygiene tips to help prevent vaginal candidiasis:
- wipe from front to back after going to the toilet - the rectal area is full of yeast
- take baths not showers - sitting in the bath can clear yeast from the vaginal area
- dry yourself thoroughly afterwards, especially the pubic hair - use a hair dryer on low setting if you have to
- don't use soap around the vagina - soap kills the bacteria you want to keep, and has no effect on yeast
- sterilize or throw away underwear that you wore during your last infection - the washing machine isn't hot enough, you must boil them if you want to keep them. You must also replace any diaphragms or caps.
- avoid chemicals like deodorant tampons and especially vaginal douches, which serve no purpose and may cause infection
These sensible precautions may also help prevent candidiasis:
- wear loose cotton underwear
- avoid pantyhose and tight pants
- eat live yogurt, especially if you have been prescribed antibiotics or have other factors which increase your risk for yeast infections - pasteurized yogurt isn't effective. Some health food stores carry lactobacillus acidophilus pills which may help to keep yeast in check
- cut down on sugar and alcohol (yeast's favourite foods)
- consider changing "the pill" - if you've had recurring infections, talk to your doctor about changing your birth control pill and see if it helps
- make sure your partner is not infected - there's no point curing candidiasis if you're going to be re-infected
- don't ask for antibiotics if you've got a cold or the flu - the flu is caused by viruses, so taking antibiotics won't help and they might provoke candidiasis
*All medications have both common (generic) and brand names. The brand name is what a specific manufacturer calls the product (e.g., Tylenol®). The common name is the medical name for the medication (e.g., acetaminophen). A medication may have many brand names, but only one common name. This article lists medications by their common names. For information on a given medication, check our Drug Information database. For more information on brand names, speak with your doctor or pharmacist.