A yeast infection is a fungal infection caused by an overgrowth of Candida species, most commonly Candida albicans, affecting areas such as the vagina, mouth, or skin. In women, vaginal yeast infections often cause itching, burning, soreness, unusual discharge, and irritation during urination or sexual activity. Oral yeast infections (thrush) can produce white patches, redness, and discomfort in the mouth or throat. Skin infections may appear as red, itchy rashes in warm, moist areas such as under the breasts, between folds of skin, or in the groin. While yeast infections are common and usually not serious in healthy individuals, they can be more frequent or severe in people with weakened immune systems, diabetes, hormonal changes, or prolonged antibiotic use.