Which of the following skin conditions is characterized by the presence of brown spots on the face due to hormonal changes during pregnancy?

Chloasma, also known as melasma, is a skin condition characterized by the appearance of brown or gray-brown patches on the face, particularly on areas that are exposed to sunlight, such as the cheeks, forehead, and upper lip. This condition is often associated with hormonal changes, especially during pregnancy, which is why it is frequently referred to as the "mask of pregnancy." The pigmentation occurs due to an increase in melanin production stimulated by hormonal fluctuations, particularly estrogen and progesterone.

In contrast, ephelides, commonly known as freckles, are small, tan or light brown spots that typically appear on the skin in response to sun exposure but are not primarily hormonally induced. Papillomas are benign growths, often referred to as warts or skin tags, caused by viral infections. Lentigo refers to a flat, brown spot that generally develops as a result of sun exposure, independently of hormonal influences.

These distinctions clarify that chloasma is specifically linked to hormonal changes during pregnancy, making it the correct choice for this question.