A-Z OF SKIN

Also known as … Acquired Naevus of Ota-like Macules (ABNOM) and Naevus Fusco-caeruleus Zygomaticus

What is Hori’s nevus?

Hori’s Naevus presents as benign (harmless) blue-grey to grey-brown patchy and spotty pigmentation on the prominence of the cheeks. The condition usually appears in adulthood. It is most common in middle-aged Asian women.

The condition is often misdiagnosed as it may resemble or coexist with melasma.

Genetics and hormones play a role in the development of Hori’s Naevus.

In normal skin, melanin-producing pigment cells (melanocytes) are present only in the upper layer of skin (the epidermis) and hair follicles. However, when these cells are present in the underlying area of skin (the dermis) it causes a condition known as dermal melanocytosis. Dermal melanocytosis is a spectrum of conditions and includes Mongolian spots, naevus of Ota, Hori’s Naevus and naevus of Ito.

When melanin is present more deeply in the skin, it results in the perceived colour changes from black-brown to blue-grey.

Hori’s Naevus presents as bilateral and symmetrical small, greyish-brown to blue-grey spots on the prominence of the cheeks and less often the temples, nose, eyelids and forehead.

The diagnosis is based on clinical examination. However, in rare cases a skin biopsy is needed.

Hori’s Naevus can be treated with the Q-switched ruby laser, Q-switched alexandrite laser or Q-switched Nd:YAG lasers. Multiple sessions (at least 4) are usually necessary.

Temporary tanning of the skin (post-inflammatory pigmentation) can complicate treatment. However, this usually settles over time. The risk of post-inflammatory pigmentation is increased if melasma is also present. The melasma will also need medical treatment.

The prognosis of subcutaneous fat necrosis of the newborn is overall favourable. Rarely, some lesions may end up shrunken-looking (atrophic) or slightly pigmented. As mentioned, hypercalcemia needs to be monitored even after the disappearance of the skin lesions.