Rare Pulmonology News

Disease Profile

Epidermal nevus

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.


US Estimated

Europe Estimated

Age of onset





Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable



An epidermal nevus is a noncancerous (benign) patch of skin caused by an overgrowth of skin cells. The nevi (plural form of nevus) are seen at birth or develop in early childhood. They can be flat, tan patches of skin, or raised, velvety patches and may become thicker and darker and develop a wart-like (verrucous) appearance. Often, epidermal nevi follow a pattern on the skin known as the “lines of Blaschko”. Sometimes, people with an epidermal nevus may have problems in other body systems, such as the brain, eyes, or bones; these people are said to have an epidermal nevus syndrome, which is a group of different disorders.[1][2][3][4] Mutations associated with an epidermal nevus are present only in the cells of the nevus, not in the normal skin cells surrounding it, and may involve the FGFR3, PIK3CA or, HRAS genes.[4][5] Treatment is challenging and may include topical medication and surgery.[4][5]


This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
Percent of people who have these symptoms is not available through HPO
Melanocytic nevus
Beauty mark
Numerous nevi
Numerous moles
Somatic mosaicism

Learn more

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • DermNet New Zealand is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.
  • Genetics Home Reference (GHR) contains information on Epidermal nevus. This website is maintained by the National Library of Medicine.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 


  1. Epidermal Nevus. Genetics Home Reference. 2011; https://ghr.nlm.nih.gov/condition/epidermal-nevus.
  2. Epidermal naevi. DermNetNZ. 2016; https://www.dermnetnz.org/lesions/epidermal-naevi.html.
  3. Epidermal Nevus Syndromes. NORD. 2016; https://rarediseases.org/rare-diseases/epidermal-nevus-syndromes/.
  4. Epidermal nevus. OMIM. 2015; https://www.omim.org/entry/162900.
  5. Wright TS. Epidermal nevus and epidermal nevus syndrome. UpToDate. January 16, 2016; https://www.uptodate.com/contents/epidermal-nevus-and-epidermal-nevus-syndrome.