Causes of thrush
Thrush is caused by an overgrowth of the yeast Candida albicans. This fungus is usually a harmless inhabitant of the gastrointestinal tract, skin and vagina, but it can overgrow opportunistically and cause infections.
Normally, host defences act locally in the vagina to combat infection and to keep levels of Candida under control. 'Protective' vaginal bacteria produce lactic acid to create an acidic vaginal environment that is hostile to other invading micro-organisms such as Candida albicans. However, there is a multitude of factors, or triggers, such as side-effects of broad spectrum antibiotics or levels of oestrogen hormone, which may alter the vaginal pH balance, destroy the 'protective' bacteria and increase risk of infection.
Gynaecological fungal infections are the body's response to external and internal influences.
Main triggers of thrush include:
- Intake of medicines such as antibiotics
- Trauma of sexual activity or use of tampons
- Stress
- Perfumed soap, shower gels and bubble baths
- Periods and menstruation
- Wearing of tight clothing
- Pregnancy.
Vaginal thrush is a mild to moderate infection and usually responds well to topical preparations or systemic treatment with oral antifungals. Thrush that is recurrent or severe (for example in women suffering from diabetes) should be referred to their GP for further investigation as there may be other reasons for their symptoms.
If your patients want to know why they have thrush or what may have caused it, try to think of any relevant factors that may apply to their particular case.
- Thrush is virtually unknown before the menarche.
- Hormonal fluctuations begin with onset of menstruation.
- Personal hygiene habits may change.
- Fashion begins to influence clothing – consider tight trousers, tights, synthetic materials.
- Many girls of this age become sexually active
- The time when many women experience thrush for the first time.
- Yeasts are detected in the vagina of 30% of pregnant women.
- Hormonal fluctuations can have a negative influence on the vaginal environment and immunological defence.
- Hormone fluctuations.
- Oestrogen HRT.
- Altered glucose tolerance, may occur post-menopause, and can reduce immune response.
- Thinning of the vaginal epithelium and increased dryness.
Also, remember the other contributory factors that may increase a woman’s risk of contracting vaginal candidiasis.
- Can alter the body’s immune status.
- These drugs can reduce the quantity of “friendly” bacteria.
- Can increase risk of asymptomatic colonisation with candida.
- Poor control can increase risk of symptomatic infection.
- Disease-related, e.g: cancers, HIV, malnutrition.
- Therapy-related, e.g: corticosteroids, immuno-suppressants, irradiation.
