Vaginal thrush aka Vulvovaginal Candidiasis (VVC), aka vaginal yeast infection is a fungus gone wild. VVC is caused by a fungus or yeast called Candida. While not everything is understood about the unusual behaviour of the fungus and causes of the terrible symptoms, such as itching, burning, pain, discharge, swelling, tears or excoriations, painful sex, or burning with urination, we do know that environmental triggers play the biggest role.
Candida has many species but the most common cause of VVC is due to Candida albicans in 80-90% of the cases. Heat, elevation in pH, antibiotics (that kill off the good bacteria called lactobacillus), glucose, and moisture are the biggest culprits. It is not considered a sexually transmitted disease, but male partners can develop balanitis (yeast infection of the penis) if a woman is infected. It usually resolves on its own with washing and keeping the area dry.
Normally, Candida lives in or on our bodies, primarily in the mouth, intestines, vagina, and on the skin. They live in the dormant state most of the time in the shape of little oval buds—just hanging out and doing nothing bad. When triggered, they morph into different shapes called hyphae and pseudo-hyphae, otherwise known as the ‘filamentous forms,’ which are the infectious forms that cause the condition. What happens is the filamentous forms grow larger and invade the tissue sort of like roots or branches. Once that occurs, the immune system is notified that something foreign is trying to get deeper into the tissue, so it is activated to release specialized white blood cells, called neutrophils or polymorphonuclear neutrophils (PMNs) to be exact. PMNs come out in force and try to kill off the hyphae, but end up dying and releasing their inner contents—a bunch of enzymes that cause distinct itching, irritation, and even pain.
About 75% of women will get a yeast infection in their lifetime while about 30-50% will have more than one outbreak. Not everyone gets the characteristic discharge that is described as similar to cottage cheese or curd-like. Many times, it goes straight to pain and skips the itch. Then, you get redness, swelling, or even small tears in the labia minor and areas nearby. While it starts in the vagina, most of the symptoms are around the hymen or introitus region, where nerves are more abundant. Sometimes, the only warning of the infection is pain during intercourse. The area gets very sore and feels dry and raw.
Symptoms of yeast infections
- Pain, discharge-white and thick
- Excoriation or fissures
- Pain as urine contacts vulva during urination (this is different than burning with the onset of urination)
- Painful sex
Risk factors or predisposing factors for VVC
- Elevated pH -5.0 or above
- Altered microbiome
- Antibiotics kill off the normal microbiome—lactobacillus and corynebacterium which are responsible for producing lactic acid, hydrogen peroxide, and acetic acid to keep the pH relatively acidic
- Hormonal contraception
- Sexual activity of any kind—however, you can get VVC even if you have never had sex
- Hygienic products like douches or wipes with fragrances
- Moisture from urine or other fluids such as sweat or wet bathing suits
- Immunodeficiency states such as HIV
Women who get four or more outbreaks of VVC in a given year are considered to have Recurrent Vulvovaginal Candidiasis or RVVC. This likely reflects a genetic predisposition and possibly a defect in local immune function. It is thought that about 5% have RVVC but since the problem is often treated OTC (over the counter), that number may be much higher.
Treatment of VVC
Topical creams or suppositories are the most commonly available treatment options, and they are available over the counter. An oral prescription drug fluconazole is generally reserved for recurrent sufferers and more severe cases that do not respond to topical creams. See Table 1 for all the available treatment options.
It should be noted that there is often a delay in symptom relief for all formulations and many topical drugs can worsen symptoms initially. So, have a plastic bag of crushed ice handy just in case. You must use the creams or suppositories at night so that it does not leak out right away. When you wake up, it’s best to insert a tampon (if you can) to prevent the drug from leaking and irritating you externally.
Recommended Treatment for Vulvovaginal Candidiasis:
|Intravaginal Agents (on of following)||Brand name||Duration|
|Butoconazole 2% cream||Mycelex 3||3 daysa|
|Butoconazole 2% sustained release||Gynazole-1||single dose|
|Clotrimazole 1% cream||Gyne-Lotrimin-7, Mycelex-7||7–14 daysa,b|
|Clotrimazole 100 mg vaginal tablet||Gyne-Lotrimin-7||7 days|
|Clotrimazole 100 mg vaginal tablet||Gyne-Lotrimin-7||3 days|
|Clotrimazole 500 mg vaginal tablet||Gyne-Lotrimin||single dose|
|Miconazole 2% cream||Monistat-7||7 daysa,b|
|Miconazole 100 mg suppository||Monistat-7||7 daysa|
|Miconazole 200 mg suppository||Monistat-3||3 daysa|
|Nystatin 100,000 unit vaginal tablet||Mycostatin||14 days|
|Tioconazole 6.5% ointment||Monistat 1-Day, Vagistat 1||single dosea|
|Terconazole 0.4% cream (45 gms)||Terazol-7||7 daysb|
|Terconazole 0.8% cream (20 gms)||Terazol-3||3 days|
|Terconazole 80 mg suppository||Terazol-3||3 days|
Available over-the-counter. Recommended during pregnancy.
Adapted from Mashburn J. Etiology, Diagnosis, and Management of Vaginitis. J Midwifery Womens Health 2006; 51:423–30 and Centers for Disease Control and Prevention.
- Katz. Vaginitis. Katz. Comprehensive Gynecology. 5th ed. Mosby; Elsevier; 2007. 588-596.
- Szumigala JA, Alveredo R. Vulvovaginitis. Ferri. Ferri's Clinical Advisor 2009. Mosby; Elsevier; 2009. 155, 1008-1012.
- Eckert LO. Clinical practice. Acute vulvovaginitis. N Engl J Med. 2006 Sep 21. 355(12):1244-52.
- Margesson LJ. Vulvar disease pearls. Dermatol Clin. 2006 Apr. 24(2):145-55, v
- Foxman B, Muraglia R, Dietz JP, Sobel JD, Wagner J. Prevalence of recurrent vulvovaginal candidiasis in 5 European countries and the United States: results from an internet panel survey. J Low Genit Tract Dis. 2013 Jul. 17(3):340-5
- Yano J, Peters BM, Noverr MC, Fidel PL Jr. Novel Mechanism behind the Immunopathogenesis of Vulvovaginal Candidiasis: “Neutrophil Anergy”. Infect Immun. 2018 Feb 20;86(3):e00684-17. doi: 10.1128/IAI.00684-17. PMID: 29203543; PMCID: PMC5820946.
- Nyirjesy P. Vulvovaginal candidiasis and bacterial vaginosis. Infect Dis Clin North Am. 2008 Dec. 22(4):637-52, vi.