What is Sebaceous nevus?
A sebaceous nevus is a type of birthmark that usually appears on the scalp. It may also appear on the face but this is less common. It consists of overgrown epidermis (upper layers of the skin), sebaceous glands, hair follicles, apocrine glands and connective tissue.
It starts as a flat pink or orange plaque. Hair does not grow in the nevus. Typically, these are fairly small areas of skin. However, they can sometimes be larger and more noticeable.
These birthmarks usually look the same until puberty. Hormonal changes cause them to become more raised. During adolescence they can become very bumpy and wart-like. This can make them bothersome when brushing, combing or cutting the hair.
The cause is unknown.
As a person gets older, typically after adolescence, abnormal changes to the sebaceous nevus can sometimes occur.
Diagnosis
Your doctor can usually diagnosis this kind of birthmark. If unsure, the doctor may take a small piece of the birthmark as a biopsy.
Treatment
Generally, it is very safe to simply watch a sebaceous nevus over time. It does not go away on its own.
A sebaceous nevus will not affect your health, but you may still want it to be taken off. If it is large or becomes bothersome, it may be removed. If there are abnormal changes to the area, it may also be removed.