Hori’s Nevus (Bilateral Acquired Nevus of Ota)

Introduction

• It is a skin disorder which concerns mainly Asians
• Clinically, Hori’s Nevus can coexist with melasma (chloasma, pregnancy mask) and or solar lentigos. It can be difficult to distinguish them*.

*But it is important to distinguish them as Hori’s nevus responds well to the Nd-YAG 1064nm laser. However, solar lentigos (lentigenes) respond well to the Nd-YAG 532nm Q-Switched laser.

How does it look like ?

• It presents as roundish bluish macules located on the cheeks.
• They appear blue because of the Tyndall effect.

  

  Hori’s Nevus (Courtesy of Professor Goh CL)

What is it caused by ?

• The genetic factors are unknown; so are the origin of the melanocytes
• It is thought that the melanocytes could be present at birth and become visible in the twenties and thirties with sunexposure.

Does it go away on its own ?

• In contrast with Mongolian spots, it has a tendency to persist.
• In contrast with Mongolian spots and like the Nevus of Ota, Hori’s Nevus is surrounded by an extracellular sheath. This persistant sheath does not allow pigmentation to exit.

How to treat it ?

• Topical treatments are often ineffective.
• Hori’s Nevus responds well to the Nd-YAG 1064nm laser.

Contributors:

Dr Christophe HSU – dermatologist. Geneva, Switzerland

Source of Information: SY 20. Hyperpigmentation. Goh BK. Hyperpigmentary Disorders. Challenges and controversies. 2012 (06) – 9th Spring Symposium of the EADV (European Academy of Dermatology and Venerology) – Verona, Italiy (Italia)