Candida albicans is a widespread organism with worldwide distribution. It is normally found in small amounts in the vagina, the mouth, the digestive tract, and on the skin without causing disease or symptoms (approximately 25% of women without disease symptoms have this organism present).
Symptoms appear when the balance between the normal microorganisms of the vagina is lost, and the Candida albicans population becomes larger in relation to the other microorganism populations.
This happens when the environment (the vagina) has certain favorable conditions that allow growth and nourishment of Candida albicans. An environment that makes it difficult for the other microorganisms to survive may also cause an imbalance and lead to a yeast infection.
Yeast infection may follow a course of antibiotics (particularly tetracycline) that were prescribed for another purpose. The antibiotics change the normal "balance" between organisms in the vagina by suppressing the growth of protective bacteria that normally have an antifungal effect.
Infection is common among women who use estrogen-containing birth control pills and among women who are pregnant. This is due to the increased level of estrogen in the body. The increased hormone level causes changes in the vaginal environment that make it perfect for fungal growth and nourishment.
Yeast infections may also occur in association with diabetes or problems that affect the immune system (such as AIDS or the HIV virus).
Vaginal candidiasis is not considered a sexually transmitted disease. However, 12% to 15% of men will develop symptoms such as itching and penile rash following sexual contact with an infected partner.
Close attention should be paid to episodes of vaginal candidiasis. Repeat infections that occur immediately following therapy, or a persistent yeast infection that does not respond to therapy, may be the first or, at least, an early sign that an individual is infected with HIV.
Both males and females with HIV infection who have developed AIDS may be subject to disseminated infection with Candida, including oral candidiasis (in the mouth), esophageal candidiasis (in the esophagus), and cutaneous candidiasis (on the skin).
