Vaginitis: Trichomoniasis, Candidiasis, Bacterial Vaginosis

Definition

Vaginitis is inflammation of the vagina caused by infectious agents, leading to discharge, odor, pruritus, and discomfort. Common causes include Trichomoniasis (protozoal), Candidiasis (fungal), and Bacterial Vaginosis (dysbiosis of vaginal flora).

Epidemiology

• Affects women of reproductive age; prevalence varies by etiology.
• Trichomoniasis: ~3–5% prevalence in sexually active women worldwide.
• Candidiasis: up to 75% of women experience at least one episode in lifetime; recurrent in 5–8%.
• Bacterial Vaginosis: most common cause of vaginal discharge; prevalence 10–30%, higher in sexually active women.
• Risk factors: sexual activity (Trichomoniasis, BV), antibiotics (Candidiasis, BV), hormonal changes, immunosuppression, poor hygiene.

Etiology

• Trichomoniasis: *Trichomonas vaginalis*, sexually transmitted protozoan.
• Candidiasis: *Candida albicans* or non-albicans species, overgrowth of normal flora.
• Bacterial Vaginosis: polymicrobial overgrowth (mainly *Gardnerella vaginalis*, *Atopobium vaginae*) with loss of lactobacilli.
• Predisposing factors: diabetes, pregnancy, immunosuppression, antibiotics, hormonal contraception.

Pathophysiology

• Trichomoniasis: protozoan adheres to vaginal epithelium, causing inflammation, increased neutrophils, and discharge.
• Candidiasis: fungal overgrowth triggers inflammatory response with pseudohyphae formation and epithelial irritation.
• Bacterial Vaginosis: imbalance of vaginal flora with decreased lactobacilli, increased anaerobes, elevated vaginal pH, and production of amines causing odor.
• Inflammatory response causes pruritus, erythema, and mucosal irritation.