Candidiasis

Vaginal candidiasis results from overgrowth of Candida albicans when the vaginal microbiota balance is disrupted. Normally, C. albicans exists as a harmless commensal organism regulated by lactobacilli dominance. Immunosuppression, antibiotic use, hormonal changes, or declining lactobacilli numbers allow Candida to proliferate and transition to a pathogenic hyphal form.

Under favorable conditions, C. albicans shifts from a benign yeast form to an invasive hyphal form. This morphological change is triggered by disrupted vaginal conditions, including increased pH. The hyphal form is particularly virulent and capable of adhering to and penetrating vaginal tissue, making it pathogenic compared to the commensal yeast form.

The hyphal form of C. albicans secretes hydrolytic enzymes, including aspartyl proteases and phospholipases, which degrade epithelial barriers and immune proteins. Additionally, C. albicans forms biofilms—structured microbial communities in an extracellular matrix—that resist antifungal treatments and limit immune cell access, enhancing tissue invasion and persistence.

The immune system triggers an inflammatory cascade involving neutrophils and macrophages recruited to the infection site. While these cells work to control the infection, their inflammatory activity can worsen symptoms. This immune response produces burning, swelling, itching, and thick white discharge characteristic of vaginal candidiasis.

Lactobacilli maintain vaginal health by producing lactic acid, which keeps the vaginal pH slightly acidic and prevents Candida overgrowth. Under normal conditions, lactobacilli dominance regulates C. albicans as a harmless commensal organism. Decline in lactobacilli numbers due to antibiotics or other factors removes this protective barrier, allowing Candida proliferation.

Candidiasis is an opportunistic fungal infection affecting various anatomical sites, including the skin, oral cavity, nails, and genitourinary tract. While vaginal candidiasis is the most common form of mucosal infection, the same Candida species can cause disease at multiple body locations depending on local conditions and immune status.

Recurrent candidiasis may involve non-albicans Candida species or indicate underlying immune or microbial imbalances requiring further evaluation. Persistent disruption of the vaginal microbiota or immunosuppression can prevent effective clearance of the fungus. Recurrent infections suggest the need to address root causes such as antibiotic overuse, hormonal factors, or compromised immune function.