What condition involves the darkening of certain areas of the skin?

The condition that involves the darkening of certain areas of the skin is known as chloasma, also referred to as melasma. This condition is characterized by the development of brown or gray-brown patches, often on the face, particularly on the cheeks, forehead, nose, or upper lip. It is commonly associated with hormonal changes, which can occur during pregnancy, the use of oral contraceptives, or hormone replacement therapy. Sun exposure can also exacerbate the condition, further emphasizing the darker pigmentation in those areas.

In contrast, the other conditions mentioned do not involve darkening of the skin. Vitiligo is characterized by the loss of skin pigment, leading to lighter patches on the skin. Hyperhidrosis pertains to excessive sweating and does not affect skin pigmentation. Dermatitis refers to inflammation of the skin, which may cause redness or irritation but does not inherently result in darkened skin areas.