Itch, or pruritus, is an uncomfortable sensation on the skin that triggers the urge to scratch. It can result from localized causes such as dry skin, insect bites, allergic reactions, rashes, eczema, or fungal infections, or from systemic conditions including liver disease, kidney disorders, thyroid imbalance, or certain medications. Itching may occur with or without visible skin changes and can range from mild and temporary to persistent and severe. Chronic itching can disrupt sleep, cause skin damage from repeated scratching, and significantly affect quality of life. Because pruritus may sometimes signal an underlying medical condition, persistent or unexplained itching warrants medical evaluation.