Nevus Comedonicus

Key Points
Congenital nevus which forms in a hair follicle
Exact cause is unknown, but is thought to arise as a result of a genetic abnormality
Initially consists of a single orange-yellow patch of skin, which may become warty or scaly in appearance at adolescence

Nevus comedonicus are nevi which form in hair follicles, which may occur anywhere on the body. The condition consists of the formation of comedones at the location of the nevus, which may form from sebaceous glands or sweat ducts. Lesions may appear singly, and uncommonly, in multiples. In some cases, lesions may develop Acne during puberty, which may lead to scarring. Additionally, the condition is in rare cases associated with additional abnormalities, resulting in comedo nevus syndrome, which may cause cataracts, skeletal malformations, and developmental issues.

The exact cause of nevus comedonicus is unknown, but it is thought to develop due to a genetic abnormality. The condition is always present at birth, and may affect anyone regardless of age, gender, or ethnic group.

Differential Diagnosis (Other conditions with similar appearance)
Acne Vulgaris
Favre-Racouchot syndrome
Chloracne and Acne conglobata
Keratosis pilaris
Epidermal nevus
Lichen Striatus
Familial dyskeratotic Comedones
Nevus Sebaceus

Diagnosis
Key Points
Diagnosis based on characteristic appearance of lesions
Biopsy and other testing may be performed to confirm diagnosis and rule out other conditions

Nevus comedonicus is typically diagnosed based on the characteristic appearance of lesions. Skin biopsy and other testing may be performed to rule out other similar appearing conditions.

Treatment
Treatment is not required in lesions which are asymptomatic
Topical retinoids or keratolytic agents may be prescribed in some cases
Removal of the entire lesion is possible via surgical excision

As most Nevus comedonicus lesions are asymptomatic, treatment is not typically required. Topical retinoids or keratolytic agents may be prescribed if treatment is necessary. Additionally, lesions may be removed entirely via surgical excision.