Epidermal Nevus

Epidermal nevi are benign skin growths that result from overgrowth of the epidermis (top layer of the skin) and/or the hair and glands of the skin. They are estimated to occur in 1 of 1000 live births and affect males and females equally. Most cases arise sporadically during development of the embryo, but familial patterns of inheritance have been observed.

Presentation:
Epidermal nevi can occur in a localized area of skin or be more diffuse covering large areas of the body. The majority of epidermal nevi appear at birth or within the first year of life, however, they may also develop later during childhood or adulthood. They may be skin-colored, brown, or grayish in color and often have a linear appearance.

Other Considerations:
The presence of multiple or widespread epidermal nevi in an infant or child should prompt consideration of other organ abnormalities. These patients should be followed closely to assure attainment of developmental milestones. Large or widespread epidermal nevi can be associated with neurological problems, as well as abnormalities of the bones, eyes, urinary tract, and other organ systems. When epidermal nevi are associated with involvement of other organ systems, the condition is called epidermal nevus syndrome. Establishing this diagnosis and screening for associated abnormalities may involve skin biopsies, blood tests, urinalysis, x-rays, ultrasound, computed tomography (CT) scans or magnetic resonance imaging (MRI), and electroencephalograms (EEG).

Treatment:
Treatment is most often for cosmetic improvement, reducing disfigurement, and alleviating discomfort. Localization to cosmetically sensitive areas, such as the head and neck can be very embarrassing and distressing for patients. Extensive epidermal nevi can cover much of the body surface and, if present in areas of friction, such as the groin and armpits, can become tender and a potential source of infection.

The treatment of epidermal nevi is challenging. Multiple medical and surgical treatments have been attempted, but no ideal or universally acceptable treatment has emerged. Corticosteroids applied under occlusion or by injection, as well as tretinoin cream applied topically, may sometimes be partially effective. A class of medicine called oral retinoids may be beneficial for the treatment of widespread epidermal nevi, but may require life-long therapy. The treatment of choice for small epidermal nevi is surgical excision. Superficial means of removal frequently result in recurrence. Aggressive approaches may be more successful, but also carry a higher risk of postoperative scarring. Surgical excision, dermabrasion, cryosurgery, electrosurgery, and laser surgery have each been used to treat epidermal nevi. In particular, surgical excision always causes scar formation and thus is reserved for the smallest lesions.

Dermabrasion, if superficial, is associated with a high rate of recurrence, and deep dermabrasion can result in thickened scars. Cryosurgery has similar limitations, with the risks including slow healing, infection, swelling, and not uncommonly, abnormal coloration of the skin. Physicians have been performing laser treatment on epidermal nevi for decades. Recent advances in laser technology have increased the ease, precision, and safety of such treatments. Several reliable and effective methods for treating epidermal nevi with lasers have been developed. However, recurrences can occur months or years after removal of epidermal nevi by any method.

References:
Levenberg ME, Ermolovich T, Purcell SM. Management of epidermal nevi in the setting of epidermal syndrome. JAOCD 2006;6:58-61.

Gregg Severs, D.O.
Department of Dermatology
Philadelphia College of Osteopathic Medicine/Frankford Hospital
Philadelphia, Pennsylvannia.