Rare Rheumatology News

Disease Profile

Linear porokeratosis

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


Other names (AKA)

Congenital facial linear porokeratosis (type)


Linear porokeratosis is a rare skin condition characterized by streaks of reddish-brown patches surrounded by a ridge-like border.[1] The patches usually develop in infants or young children, but they sometimes develop in adults.[2] Patches may be on one area of the body (localized) or on multiple areas (generalized). They usually develop in a pattern over the skin known as the "lines of Blaschko," and most commonly occur on the arms or trunk.[2][1] Some people experience itching or pain where the patches occur.[2]

Linear porokeratosis is thought be a form of disseminated superficial actinic porokeratosis (DSAP). Researchers think that people with linear porokeratosis may have one inherited mutation in a gene that causes DSAP.[3] It is thought that a second mutation in that gene is acquired (a somatic mutation), occurring in only some cell lines. This may cause the presence of streaks of patches, rather than more widespread patches.[3][1][2]

Treatment options depend on each person's symptoms. There are no specific recommendations for treatment because no randomized clinical trials have been done. Options may include topical therapies, oral retinoids, cryotherapy, electrodessication, and surgery.[2] Linear porokeratosis can progress to skin cancer (squamous cell and basal cell carcinoma), so sun protection and watching for changes within patches are recommended.[1][2]


There are no established treatment recommendations for any form of porokeratosis because no randomized clinical trials have been done. Treatment options depend on each person's symptoms and concerns. Responses to treatment are unpredictable, so a person may have to try more than one treatment, or a combination of treatments.[2] Options for treatment of porokeratosis may include:[2][1]

Linear porokeratosis can progress to skin cancer (squamous cell and basal cell carcinoma). If the purpose of treatment is to prevent its progression to cancer, surgical removal is typically recommended. Sun protection is also important to decrease the risk for cancer. Watching for changes within patches may help to detect cancer earlier.[1][2]

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 NZ is an online resource about skin diseases developed by the New Zealand Dermatological Society Incorporated. DermNet NZ provides information about this condition.

In-Depth Information

  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Linear porokeratosis. Click on the link to view a sample search on this topic.


  1. Prak AH. Porokeratosis. Medscape Reference. August 7, 2017; https://emedicine.medscape.com/article/1059123-overview.
  2. Spencer LV. Porokeratosis. UpToDate. Waltham, MA: UpToDate; September 1, 2016; https://www.uptodate.com/contents/porokeratosis.
  3. Sommerlad M, Lock A, Moir G, McGregor J, Bull R, Cerio R, Harwood C. Linear porokeratosis with multiple squamous cell carcinomas successfully treated by electrochemotherapy. Br J Dermatol. December, 2016; 175(6):1342-1345. https://www.ncbi.nlm.nih.gov/pubmed/27086492.

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