The cause of epidermal nevus is thought to be a genetic abnormality, meaning that a gene either coming from the mother or the father is abnormal. This can give rise to different types of abnormal cells, on the basis of which the types of epidermal nevus are identified.

Some of the types of epidermal nevi include:

• Linear epidermal naevus
• Epidermolytic epidermal nevus
• Acantholytic epidermal nevus (Hailey-Hailey or Darier disease-like)
• Linear porokeratosis
• Systematized epidermal nevi

Most epidermal nevi do not cause any serious issues, and remain unchanged throughout adulthood. The main problem they cause are cosmetic, especially if they arise on areas of the skin that are routinely exposed such as the hands and the face. In these cases, it may be advised to seek treatment.

Treatment options for epidermal nevus can be divided into medical and surgical treatment, with the latter being the gold standard treatment. Medical treatment options include corticosteroid therapy and the use of vitamin A derivatives. These can be used both topically or via oral formulations. However, the effectiveness of medical therapy for epidermal nevi is doubtful.

Surgical treatment options have been shown to be more effective. Some of the options include shave excision, and laser vaporisation. Shave excision is a procedure performed by an experienced plastic surgeon. It is a fast and fairly reliable method for small to medium sized lesions, and this involves peeling off the unwanted, unsightly raised lesions under local anesthesia. Laser vaporisation involves the use of carbon dioxide lasers to remove the lesion and have been noted to be safer and effective especially in small lesions.

Some noteworthy points regarding the treatment of epidermal nevi is that recurrence is fairly common regardless of the type of treatment opted for. Other complications that can arise with surgical treatment include pigmentary abnormalities of the treated area, which may be either hypopigmentation or hyperpigmentation. In addition, if the epidermal nevus involves a joint surface, the healing can be delayed and a joint contracture can form which can lead to a limitation of joint functions. This is especially noted in small digital joints of hands and feet.