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Candida
Candida is a yeast which is found on the skin and in the gut of most people, whether they are healthy or unwell. Most of the time it does not cause a problem.
There are several circumstances in which Candida can become a problem.
In the gut, mouth and vagina, yeasts compete for space with the normal bacteria found in these areas. These bacteria are part of the normal gut and vaginal flora, and are required for good health and digestion. Under some circumstances the numbers of bacteria can be reduced, and this allows the number of yeasts to increase, to take up the space normally occupied by the bacteria. This may occur
- if the person takes lots of antibiotics (especially repeated courses for, say, chest infections, urinary infections, skin infections or dental abscesses) - antibiotics kill bacteria, but do not kill yeasts, which can therefore flourish.
- if the person takes medications that alter the environment in the gut / mouth / vagina (perhaps by altering the level of acidity, which bacteria require in order to flourish), such as steroids (either by tablet, or inhaled steroids used in asthma), HRT or the contraceptive pill.
People who are generally unwell, or whose immune system is not working effectively, will be more likely to suffer this problem.
In the mouth, an overgrowth of colonies of yeasts (known as thrush) generally causes a sore mouth, creamy white spots, sometimes with mouth ulcers or bleeding. Treatment is usually a course of antifungal lozenges to suck, or liquid antifungal to swill round the mouth. Nystatin or Amphoteracin are generally used. Not much of these drugs is absorbed into the body, so there is a low incidence of side-effects. Sugar-free preparations are preferred. For those wanting to use pure products, it is possible to obtain pure Nystatin powder, which can be mixed in water (it does not actually dissolve) and used as a mouthwash. This tastes very bitter, so for children the pharmacy dept at Eastbourne General Hospital makes a special preparation of pure Nystatin powder using glycerine as a sweetener. All these preparations are prescription-only.
In the vagina, yeast overgrowth (thrush) causes itching and a creamy discharge (and sometimes cystitis symptoms). Treatment consists of antifungal cream or pessaries (usually Canestan), or oral antifungal tablets - usually a single dose of something like Diflucan, which can be bought at a pharmacy without prescription. 'Natural' remedies include applying live yoghurt (unflavoured) into the vagina - this restores the natural acidity, favouring the growth of bacteria rather than yeasts, and provides some replacement bacteria. Sexual partners may also need treatment, especially if they suffer itching / burning or a discharge.
More complex problems
In the gut, an overgrowth of yeasts (normally caused by repeated antibiotics, especially in combination with steroids / hormones) may cause a number of problems.
Firstly, yeasts ferment sugars to produce gas and alcohols (although yeasts are not the only fermenters - some bacteria also ferment). Excess levels of yeasts cause more fermentation, which may give rise to symptoms such as bloating, wind, griping abdominal pain, diarrhoea, or diarrhoea alternating with constipation. These symptoms may be worse after meals containing easily-fermentable sugars. Some of the fermentation products produced may make some people feel generally ill (headaches, lethargy etc).
Secondly, excess yeast growth may be detected by the immune system, which may see the yeasts as a threat, and initiate the production of antibodies to fight the yeasts. This leads to sensitivity, or 'allergy' to the yeasts (not usually 'classic' allergy). If this happens, the immune system cells will release chemicals that make the gut wall more leaky, allowing parts of the yeast cells to escape from the gut. This will make the immune system attack the yeasts all the more, increasing the sensitivity. The increased gut leakiness (permeability) may also allow an increase in the number of large food molecules escaping through the gut wall, which may cause or exacerbate food sensitivity. (Alternatively, food allergy / sensitivity may itself cause a leaky gut, and this may lead to the development of yeast sensitivity. It may not always be clear which came first).
If antibodies are produced to attack the yeasts, these antibodies may cross-react with yeasts that are eaten. Thus the patient may 'react' to yeasts in foods such as bread, gravy, cheese, alcoholic drinks and supplements derived from yeasts. The sensitivity reactions to the yeasts in the gut or in foods may produce a variety of symptoms including nasal symptoms, rashes, urticaria, arthritis or asthma, as well as the gut symptoms and lethargy mentioned earlier.
In summary, yeast overgrowth should be considered in people who complain of bloating, wind, diarrhoea or diarrhoea/constipation, and who may also suffer lethargy, nasal symptoms, asthma, rashes / urticaria, and who have a history of repeated thrush of the mouth or vagina, lots of antibiotics, steroids or hormones. Yeast overgrowth also seems to exacerbate chemical sensitivity, so MCS sufferers should consider whether it may be relevant. Yeasts can infect eczema in the same way that bacteria can, so antifungals may be helpful in some cases.
Treatment of yeast overgrowth in the gut
Foods that may cross-react with yeast antibodies should be avoided (bread, alcoholic drinks etc as listed above, plus fruits that may be contaminated with yeasts, such as grapes, plums etc.). A low-sugar diet is probably sensible, not because it 'feeds the yeasts' but because it will provide less fermentable sugars for them to work on.
Drugs to kill yeasts in the gut include Nystatin or Amphoteracin, taken several times a day for a few weeks, or Diflucan or Sporanox taken once daily for up to 2 weeks. On the whole these have a low incidence of side-effects and are usually effective. More natural remedies include garlic, tea-tree oil and caprylic acid - these may be more gentle but are less effective and will need to be taken for longer. Pro-biotics (natural gut bacteria to replace the natural flora and compete with the yeasts) are important.
If food sensitivity has developed this will need to be tackled, partly because it will be causing some of the symptoms, and partly because if it is contributing to a leaky gut and is left untreated, it makes it more difficult to control the yeasts.
Yeast cells contain toxins which will be released when the cell dies. Some people find that starting antifungal treatments causes symptoms due to the release of toxins as large numbers of yeast cells suddenly start to die.
If sensitivity to yeasts has developed, some people might benefit from desensitisation to yeast, either by EPD or neutralisation.
Investigations
There are tests that look for antibodies to yeasts, to determine whether sensitivity has developed, and tests that measure gut fermentation products, to assess the amount of alcohol etc produced in the gut and use this to estimate how much yeast is present. These tests can be useful but are not infallible. They all need to be ordered by a Doctor, who will also be needed to interpret the results. It is important to realise that there is a difference between sensitivity to yeasts (when even a small amount may cause a problem) and overgrowth of yeast leading to fermentation-type symptoms. A different treatment approach might be required in each case.
Fungal nail infections
Yeasts and fungi can infect finger- and toe-nails, as well as the skin (this is not necessarily related to gut overgrowth etc - either can occur in isolation). There can be a connection between fungal nail infections and symptoms such as asthma, as well as any local irritation / discolouration from the infection. These infections are very difficult to treat; they are usually tackled with local application of antifungal liquids or creams over a long period of time (up to a year), but oral tablets may sometimes be used.
Author: John Collard, Allergy UK Nurse Consultant - January 2006