Vaginal infections are one of the most common gynecological complaints in primary care medicine, affecting the vast majority of women at least once in their lifetime. Unusual vaginal discharge in color, texture, or odor, vulvar itching, burning, or irritation — these symptoms, although often perceived as minor, deserve accurate medical evaluation because several different conditions can cause them, with treatments specific to each cause. Self-treating without a confirmed diagnosis — for example, with an over-the-counter antifungal for what is assumed to be a «yeast infection» — is a common mistake that can delay the treatment of another condition and contribute to resistance.
The three main causes of vaginal infections are bacterial vaginosis, yeast infections, and trichomoniasis—each with distinct symptomatic profiles, diagnostics, and treatments. Medical consultation allows for the clinical differentiation of these conditions and through rapid testing, and to rule out any associated sexually transmitted infections (STIs) when the context warrants it. Clinique Omicron offers consultations for female genital symptoms in several of its Quebec locations, with access to appropriate diagnostic tests and prescription of the suitable treatment during the same visit.
Bacterial vaginosis: The most common cause of abnormal vaginal discharge
La vaginose bactérienne (VB) est la cause la plus fréquente de pertes vaginales anormales chez les femmes en âge de procréer, résultant d’un déséquilibre de la flore vaginale normale. À l’état physiologique, le vagin est dominé par des lactobacilles (principalement Lactobacillus crispatus et Lactobacillus iners) qui maintiennent un pH acide (< 4,5) protecteur. Dans la vaginose, cette flore protectrice est supplantée par une prolifération polymicrobienne — Gardnerella vaginalis, Mycoplasma hominis, Prevotella, Mobiluncus et d’autres anaérobies — avec élévation du pH vaginal. La VB se manifeste typiquement par des pertes vaginales grises ou blanches, homogènes, fluides, avec une odeur caractéristique de « poisson » (amine) souvent accentuée après les rapports sexuels ou pendant les règles — en raison de la volatilisation des amines en milieu alcalin (sperme, sang). Environ 50 % des femmes avec vaginose sont asymptomatiques.
The diagnosis of bacterial vaginosis is based on the Amsel criteria: presence of at least 3 of the following 4 criteria - characteristic vaginal discharge (homogeneous, grey-white, adhering to the walls), vaginal pH > 4.5, positive «Whiff test» (amine odour when KOH 10 % is added to secretions), and presence of «clue cells» on direct microscopic examination (vaginal epithelial cells covered with bacteria). The reference treatment is metronidazole - orally (500 mg twice a day for 7 days) or as a vaginal gel (MetroGel-Vaginal 0.75 % applied intravaginally once a day for 5 days) - or clindamycin as a vaginal cream. Recurrences of bacterial vaginosis are very frequent (up to 50 % at 6 months), representing a major clinical challenge. Strategies to reduce recurrence include the use of vaginal lactobacillus probiotics, stopping smoking and reducing the use of vaginal douches, which disrupt the flora.
Vaginal candidiasis: yeast infection and recurring episodes
Vulvovaginal candidiasis (VVC) is caused by an overgrowth of yeasts of the genus Candida—in 80 to 90% of cases, *Candida albicans*—normally present in small amounts in the vagina without causing symptoms. Predisposing factors favor this overgrowth: recent antibiotic therapy (disruption of protective bacterial flora), pregnancy (high estrogen levels favor Candida colonization), poorly controlled diabetes (hyperglycemia favors yeast growth), immunodeficiency, prolonged corticosteroid therapy. The typical clinical presentation involves intense vulvar itching (pruritus), thick white vaginal discharge resembling «cottage cheese,» vulvar redness and swelling, and sometimes dysuria related to perineal irritation. Unlike vaginitis, candidiasis typically does not cause an abnormal odor, and vaginal pH is normal or only slightly altered.
The first-line treatment is an antifungal azole—topical intravaginal (clotrimazole, miconazole, terconazole, available over-the-counter or by prescription) or oral fluconazole 150 mg as a single dose (by prescription). Oral fluconazole is contraindicated during pregnancy. Recurrent vulvovaginal candidiasis—defined as 4 or more episodes per year—affects approximately 5–8% % of women and is a particular therapeutic challenge. Management includes mycological confirmation (culture with an antifungal susceptibility test to rule out a resistant non-albicans species such as Candida glabrata or Candida auris, which are resistant to fluconazole), identification and correction of predisposing factors, and weekly oral fluconazole maintenance therapy for 6 months (Sobel protocol) or cyclic monthly topical treatment.
ITSS, HPV vaccination, and sexual health: the role of the clinic
Trichomoniasis—caused by the protozoan *Trichomonas vaginalis*—is the most common non-viral sexually transmitted infection (STI) worldwide and a major cause of vaginitis. It manifests as yellowish-green, frothy, foul-smelling vaginal discharge, with itching, burning, and sometimes cervical «strawberry» patches (hemorrhagic cervicitis visible on examination). It is diagnosed by direct microscopic examination, NAAT (nucleic acid amplification test), or culture. Treatment is metronidazole or tinidazole (a single 2 g dose or a 7-day course), and the sexual partner must be treated simultaneously to prevent reinfection. The coexistence of multiple vaginal infections or STIs is possible—BV, for example, increases susceptibility to STIs including HIV, gonorrhea, and chlamydia by altering local mucosal defenses.
In this context of global sexual health, vaccination against the human papillomavirus (HPV) remains one of the most important preventive interventions available. The Gardasil 9 vaccine — included in Quebec's free vaccination program for adolescents in Grade 9 — protects against 9 strains of HPV responsible for 90 % of genital warts and approximately 90 % of HPV-related cancers of the cervix, anus, penis, vagina, vulva, and oropharynx. Vaccination is also recommended and available for unvaccinated adults up to age 45 — with benefits even after the onset of sexual activity, as it protects against strains not yet encountered. Clinique Omicron offers HPV vaccination as well as complete STI screening in several of its Quebec locations for integrated sexual health management.
Frequently Asked Questions about Vaginal Infections and Sexual Health
Can over-the-counter treatments for vaginal infections be used without consulting a doctor?
Over-the-counter antifungals - clotrimazole, miconazole - are legitimate and effective treatments for proven vaginal candidiasis, and women who have already had episodes diagnosed by a doctor can reasonably self-treat a recurrence with the well-known identical symptomatic picture. However, several studies have shown that when women self-treat with antifungals for vaginal symptoms, up to two-thirds of them do not have culture-confirmed candidiasis - they have another condition (bacterial vaginosis, contact dermatitis, lichen sclerosus, etc.) for which the antifungal is ineffective. This delays diagnosis and appropriate treatment. Medical consultation is recommended for any first episode, any atypical episode, any episode not responding to standard treatment, and any frequent recurrence. The doctor can perform a pelvic examination, measure vaginal pH, perform direct microscopy and refer samples to the laboratory for culture if necessary.
Is bacterial vaginosis an STD? Does your partner need to be treated?
Bacterial vaginosis is not classified as a sexually transmitted infection (STBI) in the strict sense - it can occur in women who are not sexually active, and the bacteria involved are not specific sexually transmitted pathogens. However, there is a well-documented association between sexual activity and the risk of vaginosis: a new sexual partner, multiple partners and unprotected intercourse increase the risk of BV, and women who have sex with women have a higher rate of BV than the general population, suggesting transmission between female partners. Current recommendations - notably those of the INESSS and the SOGC - do not recommend systematic treatment of male partners of women with vaginosis, as randomized trials have not shown a reduction in recurrences with this strategy. The situation is different with trichomoniasis, a true STBBI for which simultaneous treatment of both partners is essential to avoid reinfection.
How old can one be to get the HPV vaccine, and is it reimbursed in Quebec?
In Quebec, the HPV vaccine Gardasil 9 is offered free of charge under the Quebec Immunization Program (PIQ) for students in Secondary 3 (approx. 14-15 years of age), for men who have sex with men up to the age of 26, and for certain immunocompromised individuals. Outside these groups covered by the public program, the vaccine is available on prescription from clinics and pharmacies, but at the patient's expense - the cost of the complete series is several hundred dollars. The efficacy and safety data for Gardasil 9 support its use up to the age of 45. Vaccinating adults who are already sexually active remains beneficial, as it protects against HPV strains they have not yet encountered - even a person infected with a given HPV strain can benefit from protection against the 8 other strains covered by the vaccine. Efficacy is greatest when vaccination precedes any contact with the virus, but real benefit exists even after the onset of sexual activity, making it a recommended intervention for any age up to 45 not previously vaccinated.
Vaginal Candidiasis: Causes, Symptoms, Treatment, and Prevention | Clinique Omicron
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