What acquired skin disease is characterized by patches of unpigmented skin often surrounded by a heavily pigmented border?

The acquired skin disease characterized by patches of unpigmented skin typically surrounded by a heavily pigmented border is vitiligo. This condition results from the destruction of melanocytes, the cells responsible for producing melanin, which gives skin its color. As melanocytes diminish in number, affected areas lose pigment, creating distinct light-colored patches on the skin. The contrast between these patches and the surrounding pigmented skin often leads to a noticeable border around the affected areas.

Other options do not match this specific description. Ephelides, commonly known as freckles, are flat, pigmented spots that appear on sun-exposed areas and do not have unpigmented patches. Chloasma, also known as melasma, consists of dark, discolored patches typically related to hormonal changes, commonly seen in pregnancy or with hormone therapy. Albinism is a genetic condition resulting in a lack of melanin throughout the body, leading to uniformly lighter skin, hair, and eyes, rather than localized patches. Thus, vitiligo remains the correct answer for the condition described.