Nevus of Ota

(ref: DermQuest)

Nevus of Ota 

Introduction

• Nevus of Ota (Oculodermal melanocytosis) is a dermal melanocytic hamartoma that presents in childhood or at adolescence as bluish/slate gray hyperpigmentation along the first or second branch of trigeminal nerve. The pigmentation progressively increases in size and color till puberty

• Clinically, nevus of Ota presents as a blue or gray patch on the face and is within the distribution of the ophthalmic and maxillary branches of the trigeminal nerve. The nevus can be unilateral or bilateral, and, in addition to skin, it may involve ocular and oral mucosal surfaces

Pathology

• Nevus of Ota and other dermal melanocytic disorders, such as nevus of Ito, blue nevus, and mongolian spots, may represent melanocytes that have not migrated completely from the neural crest to the epidermis during the embryonic stage

Yellow arrow- Melanin and melanocytes in the dermis  (ref:IJDVL)

Presentation

Condition	Onset	Appearance	Location	Histology
Nevi of Ota and Ito	Birth/ early adolescence	Blue or gray speckled coalescing macules or patches	·         For nevus of Ota-on forehead, temple, zygomatic, or periorbital areas; ·         For nevus of Ito- the shoulder and upper arm areas	Increased dermal melanocytes
Mongolian spot	Birth	Poorly demarcated large blue-to-gray patches that tend to spontaneously resolve by age 3-6 y	Most frequently on lumbosacral areas, buttocks	Increased dermal melanocytes
Blue nevus	Congenital or acquired	Blue papules or plaques	Anywhere on skin	Increased dermal melanocytes
Melasma	Acquired; may be associated with pregnancy and other estrogen excess stages	Well-to-poorly demarcated and irregularly outlined brown patches	Maxillary and zygomatic areas on face	No increase in dermal melanocytes, presence of melanophages

Ref: Medscape

Note: For photos of Melasma and Mongolian Spots- refer to Earlier Post on " How to Decide Level of Melanin in an MCQ' posted in Feb)

Treatment

• Laser surgery is the current treatment of choice for nevi of Ota and Ito. Mongolian spot is self resolving. Q-switched lasers are advised.

Improvement post Q-Switched Laser (Ref: Kar HK, et al.  IJDVL 2011)