INTRODUCTION — Vulvovaginal candidiasis (VVC) is one of the most common causes of vulvovaginal itching and discharge. The disorder is characterized by inflammation in the setting of Candida species and results in the common vaginitis symptoms of itching and erythema. While Candida vulvovaginitis is frequently self-diagnosed, office diagnosis with microscopy is preferred.
This topic will discuss the clinical presentation, diagnostic approach, and diagnosis of VVC. Related topics on the treatment of VVC and vaginitis in general are presented separately:
●(See "Candida vulvovaginitis in adults: Treatment of acute infection".)
●(See "Vaginitis in adults: Initial evaluation".)
●(See "Bacterial vaginosis: Clinical manifestations and diagnosis".)
●(See "Trichomoniasis: Clinical manifestations and diagnosis".)
In this topic, when discussing study results, we will use the terms "woman/en" or "patient(s)" as they are used in the studies presented. However, we encourage the reader to consider the specific counseling and treatment needs of transgender and gender diverse individuals.
DEFINITION — VVC refers to a disorder characterized by signs and symptoms of vulvovaginal inflammation in the presence of and caused by Candida species. Identification of vulvovaginal Candida alone is not indicative of disease, as Candida species are part of the normal flora of approximately 25 percent of women [1]. In contrast to oropharyngeal candidiasis, it is generally not considered an opportunistic infection. VVC is not considered a sexually transmitted disease.
EPIDEMIOLOGY — VVC is the second most common infectious cause of vaginitis symptoms (after bacterial vaginosis) and accounts for approximately one-third of vaginitis cases [2]. The prevalence of VVC is difficult to determine because:
●Candida species, without inflammation, can be identified in the lower genital tract in 10 to 20 percent of healthy women in the reproductive age group, 6 to 7 percent of menopausal women, and 3 to 6 percent of prepubertal girls [3,4].
●The widespread use of over-the-counter antifungal drugs makes epidemiologic studies difficult to perform.
●The clinical diagnosis or suspicion of VVC is often based on symptoms and not confirmed by microscopic examination or culture.
●As many as one-half of clinically diagnosed women may have another condition [5].
●Culture performed without clinical correlation is likely to overestimate the prevalence of disease.
In surveys, the prevalence of VVC is highest among women in their reproductive years: 55 percent of female university students report having had at least one health care provider-diagnosed episode by age 25 years, 29 to 49 percent of premenopausal women report having had at least one lifetime episode, and 9 percent of women report having had four or more infections in a 12-month period [6,7]. Recurrent VVC is typically defined as three or more confirmed episodes in one year [8]. In a separate study, in women with an initial infection, the probability of RVVC was 10 percent by age 25 years and 25 percent by age 50 years [7]. (See "Candida vulvovaginitis in adults: Recurrent infection".)
The incidence of a single or sporadic infection increases with age up to menopause and is higher in African-American women than in other ethnic groups. The disorder is uncommon in postmenopausal women unless they are taking estrogen therapy. It is also uncommon in prepubertal girls, in whom it is frequently overdiagnosed.
MICROBIOLOGY AND PATHOGENESIS — Candida albicans is responsible for 80 to 92 percent of episodes of VVC in the United States [9,10], nonalbicans Candida species accounts for almost all of the remainder [11]. Some, but not all, investigators have reported an increasing frequency of nonalbicans species, particularly C. glabrata [12,13], possibly due to widespread use of over-the-counter drugs, long-term use of suppressive azoles, the use of short courses of antifungal drugs, and likely increased awareness due to increased diagnostic testing.
Candida organisms probably access the vagina via migration from the rectum across the perineal area [14]; cultures of the gastrointestinal tract and vagina often show identical Candida species. Less commonly, the source of infection is sexual or relapse from a vaginal reservoir. In contrast to bacterial vaginosis, VVC is not associated with a reduction in vaginal lactobacilli [15-18].
The mechanism by which Candida species transform from asymptomatic colonization to an invasive form causing symptomatic vulvovaginal disease is complex, involving host inflammatory responses and yeast virulence factors. Symptomatic disease is associated with an overgrowth of the organism and penetration of superficial epithelial cells [19-22]. One study comparing histologic specimens from women with confirmed VVC, women without infection, and women with active bacterial vaginosis reported co-invasion with Gardnerella or Lactobacillus species organisms in women with Candida infection but absence of a biofilm (in contrast with bacterial vaginosis), but causality cannot be inferred [22]. (See "Bacterial vaginosis: Clinical manifestations and diagnosis", section on 'Pathogenesis and microbiology'.)
RISK FACTORS — While sporadic attacks of VVC often occur without an identifiable precipitating factor, some risk factors or "triggers" have been identified [23,24]:
Demonstrated impact — Some diseases, endocrine changes, and medication use predispose to candida infections.
●Diabetes mellitus – Women with diabetes mellitus who have poor glycemic control are more prone to VVC than euglycemic women [25,26]. In particular, women with type 2 diabetes appear prone to nonalbicans Candida species [27]. Treatment with sodium glucose cotransporter 2 inhibitors may increase the risk for VVC [28,29]. (See "Susceptibility to infections in persons with diabetes mellitus".)
●Antibiotic use – Use of broad-spectrum antibiotics significantly increases the risk of developing VVC [30]. As many as one-quarter to one-third of women develop the disorder during or after taking these antibiotics. In one small study, administration of Lactobacillus (oral or vaginal) during and for four days after antibiotic therapy did not prevent post-antibiotic vulvovaginitis [31]. However, additional studies with better standardization of types and routes of probiotic therapy are required before definitive conclusions can be made.
●Increased estrogen levels – VVC appears to occur more often in the setting of increased estrogen levels, such as pregnancy and postmenopausal estrogen therapy.
●Immunosuppression – Candidal infections are more common in immunosuppressed patients, such as those taking glucocorticoids or other immunosuppressive drugs, or with human immunodeficiency virus (HIV) infection [32]. (See "Glucocorticoid effects on the immune system" and "The natural history and clinical features of HIV infection in adults and adolescents".)
●Genetic – An analysis of whole exome sequencing from 160 European women with recurrent VVC (RVVC) and 175 controls from the same regions demonstrated an association with polymorphisms in the SIGLEC15 gene, which produces a cell surface protein found on macrophages and dendritic cells [33]. Previous studies that evaluated known pathways identified associations between RVVC and polymorphisms in the TLR2 [34] and mannose-binding lectin genes [35]. Although these genetic variations are not modifiable risk factors, in the future, they may help guide treatment or prevention strategies.
Unclear impact — The role of various contraceptive devices, sexual behaviors, and diet on the risk of Candida vulvovaginitis is less clear.
●Combined oral contraceptives (COC) – A 2013 systematic review of the literature found that, of 12 studies including more than 200 women, 7 demonstrated a significant association between COC use and prevalent or incident candidiasis, 2 found an association that was not statistically significant, and 3 found no association or a lower risk of candidiasis. However, the authors note that among the three highest quality studies, results were evenly split: one showed an increased risk in COC users, one showed no association, and one showed reduced risk in COC users [36]. Since that review, in one study of over 1000 HIV serodiscordant couples in Zambia, COC use was associated with lower risk for candidiasis and pregnancy was associated with a higher risk compared with couples using no contraception, condoms only, or permanent contraception [37].
●Contraceptive devices – Vaginal sponges, diaphragms, and intrauterine devices (IUDs) have been associated with VVC, but not consistently. At least two studies have suggested that recurrent Candida vulvovaginitis in IUD users may be related to the ability of some species to attach to the IUD and form a biofilm rather than related to an intrinsic property of the IUD itself [38,39]. Spermicides are not associated with Candida infection. (See "Pericoital (on demand) contraception: Diaphragm, cervical cap, spermicides, and sponge" and "Intrauterine contraception: Candidates and device selection".)
●Sexual behavior – VVC is not traditionally considered a sexually transmitted disease since it occurs in celibate women and since Candida species are considered part of the normal vaginal flora. This does not mean that sexual transmission of Candida does not occur or that VVC is not associated with sexual activity. For example, an increased frequency of VVC has been reported at the time most women begin regular sexual activity [6,23,40]. In addition, partners of infected women are four times more likely to be colonized than partners of uninfected women, and colonization is often the same strain in both partners. However, the number of episodes of VVC a woman experiences does not appear to be related to her lifetime number of sexual partners or the frequency of coitus [23,41,42]. Women who exclusively have sex with women do not appear to have an increased risk of vulvovaginal infection [43].
The type of sex may be a factor. Infection may be linked to orogenital and, less commonly, anogenital sex. Evidence of a link between VVC and hygienic habits (eg, douching, use of tampons/menstrual pads) or wearing tight or synthetic clothing is weak and conflicting [23,44-51].
●Diet – There are few high-quality data examining the link between VVC and diet. Most studies are cross-sectional and have high to moderate risk of bias. A few small studies show no association between consumption of yogurt or fermented dairy products and risk for Candida vulvovaginitis [51,52]. Two studies demonstrate higher dairy consumption among women with symptomatic vulvovaginal yeast infection, though this may be due to the common practice of eating yogurt to try and reduce recurrent infections [44,53].
CLINICAL FEATURES
Symptoms — Vulvar pruritus is the dominant feature of VVC [11,20,54-56]. Vulvar burning, soreness, and irritation are also common and can be accompanied by dysuria (typically perceived to be external or vulvar rather than urethral) or dyspareunia. Symptoms are often worse during the week prior to menses [56]. The intensity of signs and symptoms varies from mild to severe, except among women with C. glabrata and other nonalbicans species infection, who tend to have mild or minimal clinical findings [57].
Physical examination — Physical examination of the external genitalia, vagina, and cervix often reveals erythema of the vulva and vaginal mucosa and vulvar edema (picture 1). Vulvar excoriation and fissures are present in approximately one-quarter of patients. However, these changes reflect nonspecific inflammation and are not necessarily specific to Candida infections. There can be little or no discharge; when present, it is classically white, thick, adherent to the vaginal sidewalls, and clumpy (curd-like or cottage cheese-like) with no or minimal odor. However, the discharge may be thin and loose, watery, homogeneous, and indistinguishable from that in other types of vaginitis. Thus, diagnosis should not be based solely on the appearance of discharge. The cervix usually appears normal.
DIAGNOSTIC APPROACH
Clinical evaluation — At the time of physical examination, a sample of vaginal discharge is collected for testing (algorithm 1). Office-based tests, pH with microscopy and point-of-care tests, provide immediate results. Alternately, the vaginal discharge can be sent for laboratory testing with molecular tests, typically nucleic acid amplification tests (NAATs). Laboratory tests may take longer for test results but have a higher accuracy [58].
Vaginal pH and microscopy — The office evaluation consists of swabbing the vaginal sidewall and discharge, assessing the vaginal pH, and performing microscopy (figure 1) [59]. The vaginal pH in women with Candida infection is typically normal (4 to 4.5), which distinguishes candidiasis from trichomoniasis or bacterial vaginosis (table 1). In mixed infections, Candida can be seen at higher pH levels. Candida species can be seen on a wet mount of the discharge; adding 10 percent potassium hydroxide destroys human cellular elements and facilitates recognition of budding yeast, pseudohyphae, and hyphae (picture 2 and picture 3 and picture 4 and picture 5 and picture 6 and picture 7) [60]. Use of Swartz-Lamkins fungal stain (potassium hydroxide, a surfactant, and blue dye) may facilitate diagnosis by staining the Candida organisms blue so they are easier to identify [61]. However, microscopy is negative in up to 50 percent of patients with culture-confirmed VVC [19].
Microscopy is also important for looking for clue cells or motile trichomonads, which indicate bacterial vaginosis and trichomoniasis, respectively, as alternative diagnoses, coinfection, or mixed vaginitis [62]. The general diagnostic approach to women with vaginal complaints is reviewed separately:
●(See "Vaginitis in adults: Initial evaluation".)
●(See "Bacterial vaginosis: Clinical manifestations and diagnosis".)
●(See "Trichomoniasis: Clinical manifestations and diagnosis".)
Nucleic acid amplification tests (NAATs) — NAATs can diagnose BV, Candida, and/or trichomonas, as well as cervicitis caused by gonorrhea and chlamydia, with sensitivities and specificities of >90 percent (table 2) [58,63-65]. NAATs can be used as the initial diagnostic tool or as a follow-up to negative microscopy in patients with high clinical suspicion (algorithm 1) [63,66-68]. Some commercial tests evaluate for single infections while others are combined tests. More discussion is available in related content. (See "Vaginitis in adults: Initial evaluation", section on 'Nucleic acid amplification tests (NAATs)'.)
Other tests — Data supporting point-of-care tests for Candida are limited [69-75].
●A DNA probe test performed in a centralized laboratory offers results comparable to culture with results available in several hours, but no speciation (Affirm VPIII).
●Polymerase chain reaction (PCR) methods have high sensitivity and specificity and a shorter turn-around time than culture [76-79] but are costly and offer no proven clinical benefit over culture in symptomatic women [76].
●Pap smear is positive in 25 percent of patients with culture-positive, symptomatic VVC [11]. It is insensitive because the cells are derived from the cervix, which is not affected by Candida vaginitis. (See "Candida vulvovaginitis in adults: Treatment of acute infection", section on 'Unique populations'.)
Limited role of culture — Culture is not typically required for the routine diagnosis of VVC because vaginal pH and microscopy are reliable tests and because yeast are normal colonizers of the vagina (ie, a culture that confirms yeast may not reflect actual infection).
We obtain a vaginal culture in:
●Patients with clinical features of VVC, normal vaginal pH, and no pathogens (yeast, clue cells, trichomonads) visible on microscopy. A positive culture in these patients confirms the diagnosis and reveals the species of Candida, thus avoiding empiric, unindicated, or incorrect therapy.
●Patients with persistent or recurrent symptoms because many of these patients have nonalbicans infections and/or infections that are resistant to azoles. C. glabrata is not easily recognized on microscopy because it does not form hyphae or pseudohyphae [2].
•(See "Candida vulvovaginitis in adults: Recurrent infection", section on 'Azole-resistant infection'.)
To perform a culture, a vaginal sample is obtained from the lateral wall using a cotton-tipped swab and inoculated onto Sabouraud agar, Nickerson medium, or Microstix-Candida medium; these media perform equally well [11]. Culture for Candida does not require quantification of in vitro colony count. Speciation of Candida is not essential for primary diagnostic testing, as most isolates are C. albicans; however, species identification is essential in refractory and recurrent disease.
Self-diagnosis — Self-diagnosis of VVC is frequently inaccurate and should be discouraged [59,80,81]. In a study that administered a questionnaire to 600 women to assess their knowledge of the symptoms and signs of VVC (and other infections) after reading classic case scenarios, only 11 percent of women without a previous diagnosis of VVC correctly diagnosed this infection [80]. Women who had had a prior episode were more often correct (35 percent) but were likely to use over-the-counter drugs inappropriately to treat other, potentially more serious, gynecologic disorders.
In another report, the actual diagnoses in 95 women who self-diagnosed VVC were VVC (34 percent), bacterial vaginosis (19 percent), mixed vaginitis (21 percent), normal flora (14 percent), Trichomonas vaginitis (2 percent), and other (11 percent) [81]. Women with a previous episode of VVC and those who read the package insert for their over-the-counter medication were not more accurate in making a diagnosis than other women.
Some consequences of misdiagnosis and inappropriate therapy include a delay in correct diagnosis and treatment, wasted monetary expenditure, and precipitation of vulvar dermatitis.
DIAGNOSIS — The diagnosis of VVC is confirmed by the presence of Candida on wet mount, nucleic acid amplification test, Gram stain, or culture of vaginal discharge in a woman with characteristic clinical findings (eg, vulvovaginal pruritus, burning, erythema, edema, and/or curd-like discharge attached to the vaginal sidewall) and no other pathogens to account for her symptoms [59]. (See 'Clinical features' above.)
As none of the clinical manifestations of VVC are pathognomonic, suspected clinical diagnosis should always be confirmed by laboratory methods (ie, microscopy, Gram stain, or culture). Once the diagnosis is confirmed, the infection is then categorized as complicated or uncomplicated to facilitate treatment (table 3). Treatment of Candida vulvovaginitis is reviewed separately. (See "Candida vulvovaginitis in adults: Treatment of acute infection".)
DIFFERENTIAL DIAGNOSIS — Importantly, although vulvar pruritus is a cardinal symptom of the disorder, less than 50 percent of women with genital pruritus have vulvovaginitis candidiasis [82].
●Normal vaginal pH – Other conditions considered in the differential diagnosis of vulvovaginitis with normal vaginal pH include hypersensitivity reactions, allergic or chemical reactions, contact dermatitis, neuropathic itch, and inflammatory dermatoses (eg, psoriasis, eczema, lichen sclerosus and lichen planus) [83]. Recognizing local adverse reactions to topical agents avoids the prescribing of additional agents that can worsen symptoms. These conditions are discussed in detail elsewhere. (See "Vulvar dermatitis".)
In addition, mechanical irritation due to insufficient lubrication during coitus can also result in vaginal discomfort.
●Elevated vaginal pH – If vaginal pH exceeds 4.5 or excess white cells are present, mixed infection with bacterial vaginosis or trichomoniasis may be present. Mixed infection (≥2 pathogens and all are symptomatic) is estimated to occur in <5 percent of patients; coinfection (≥2 pathogens but some are not symptomatic) is more common: 20 to 30 percent of women with bacterial vaginosis are coinfected with Candida species [62]. (See "Bacterial vaginosis: Clinical manifestations and diagnosis" and "Trichomoniasis: Clinical manifestations and diagnosis".)
When significant white cells are present, desquamative inflammatory vaginitis should also be considered in the differential [84]. (See "Desquamative inflammatory vaginitis (DIV)".)
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Gynecologic infectious diseases (non-sexually transmitted)".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Vulvovaginal yeast infection (The Basics)" and "Patient education: Vulvar itching (The Basics)")
●Beyond the Basics topics (see "Patient education: Vaginal yeast infection (Beyond the Basics)")
SUMMARY AND RECOMMENDATIONS
●Microbiology – Candida is considered part of the normal vaginal flora, but overgrowth of the organism can result in vulvovaginitis. Candida albicans accounts for 80 to 92 percent of episodes of vulvovaginal candidiasis (VVC); Candida glabrata is the next most common species. (See 'Epidemiology' above and 'Microbiology and pathogenesis' above.)
●Risk factors – Risk factors for Candida vulvovaginitis include diabetes mellitus, antibiotic use, elevated estrogen levels (eg, pregnancy, topical estrogen therapy), and immunocompromise. However, many women with sporadic or recurrent infection have no identifiable risk factors. (See 'Risk factors' above.)
●Clinical presentation – Vulvar pruritus is the dominant symptom. Vulvar burning, soreness, and irritation are common and may result in dysuria and dyspareunia. The vulva and vagina appear erythematous, and vulvar excoriation and fissures may be present. There is often little or no discharge; when present, it is classically white, thick, adherent, and clumpy (curd-like or cottage cheese-like) with no or minimal odor. (See 'Clinical features' above.)
●Diagnosis – The diagnosis of VVC is based on the presence of Candida on wet mount microscopy, nucleic acid amplification test (NAAT), Gram stain, or culture of vaginal discharge in a woman with characteristic clinical findings (algorithm 1 and figure 1). (See 'Clinical evaluation' above.)
●Role of vaginal culture – Culture is not necessary for diagnosis if microscopy shows yeast but should be obtained in some individuals (see 'Limited role of culture' above):
•Individuals with clinical features of VVC, normal vaginal pH, and negative microscopy.
•Individuals with persistent or recurrent symptoms because many of these women have yeast infection resistant to azoles.
●Differential diagnosis – The differential diagnosis of vulvar pruritus and erythema varies based on the vaginal pH of the affected women. For women with a normal pH, possible etiologies include hypersensitivity reactions, allergic or chemical reactions, and contact dermatitis. For women with vaginal pH above 4.5, or if excessive white blood cells are present, they can have mixed infection (eg, with bacterial vaginosis or trichomoniasis) or other dermatoses (eg, lichen sclerosus, lichen planus, or desquamative inflammatory vaginitis). (See 'Differential diagnosis' above.)
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