Hyperpigmentation is a common skin condition where certain areas of the skin become darker than the surrounding skin due to excess melanin production. This condition can be caused by various factors, including sun exposure, hormonal changes, certain medications, and skin injuries or inflammation. Types of hyperpigmentation include melasma, which is often triggered by hormonal changes; sun spots, which result from prolonged sun exposure; and post-inflammatory hyperpigmentation, which occurs after skin injuries like acne or eczema.