Final answer:
Hori's naevus, or acquired bilateral naevus of Ota-like macules (ABNOM), is a benign dermatological condition presenting as blue-gray or brown facial macules, more common in women and people of Asian descent. A dermatologist must diagnose it as the cause and accumulation of melanocytes in the skin's dermal layer differ from other pigmentation conditions.
Step-by-step explanation:
Hori's naevus, also known as acquired bilateral naevus of Ota-like macules (ABNOM), is a dermatological condition characterized by symmetrical blue-gray or brown macules. These macules primarily appear on the face, especially on the cheeks and temples. The condition is more common in women and people with a darker skin complexion, particularly those of Asian descent. Although the exact cause of Hori's naevus is not fully understood, it is believed to involve the accumulation of melanocytes (pigment-producing cells) in the middle layer of the skin (dermis), rather than the top layer (epidermis), which is the case for most other types of skin pigmentation.
Hori's naevus is usually benign and does not require treatment, but if desired for cosmetic reasons, options such as laser therapy can be used to lighten the pigmented areas. It is important to distinguish Hori's naevus from other pigmentary disorders, making diagnosis by a dermatologist essential.