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Disease Profile

Disseminated superficial actinic 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 and Genetic Diseases; Skin Diseases


Disseminated superficial actinic porokeratosis (DSAP) is a skin condition that causes dry, scaly patches.[1] Symptoms include a large number of small, brownish patches with a distinctive border, found most commonly on sun-exposed areas of the skin (particularly the lower arms and legs).[1][2] DSAP usually starts during the third or fourth decade of life and rarely affects children. Lesions generally are more prominent in the summer and less prominent in the winter. While DSAP is usually not cancerous, squamous cell carcinoma or Bowen’s disease may occasionally develop within patches.[3] DSAP may be inherited in an autosomal dominant matter or may occur in people with no family history of DSAP.[3] Some cases are caused by a change (variant) in the MVK or SART3 genes.[3][4] There is no standard treatment for DSAP, and treatment is generally not effective long-term.[1][2] Sun avoidance may reduce the development of new patches.[1] Treatments that have been beneficial in some people include topical imiquimod cream, topical 5-fluorouracil, and topical vitamin D analogs such as tacalcitol and calcipotriol. A newer therapy that has been successful is topical cholesterol/lovastatin.[5] Other therapies that have been tested with varying results include cryotherapy, electrodessication (using electrical currents to remove patches), laser ablation, and photodynamic therapy.[1][2][3]


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:
80%-99% of people have these symptoms
30%-79% of people have these symptoms
Cutaneous photosensitivity
Photosensitive skin
Photosensitive skin rashes
Sensitivity to sunlight
Skin photosensitivity
Sun sensitivity

[ more ]

5%-29% of people have these symptoms
Itchy skin
Skin itching

[ more ]

Squamous cell carcinoma


Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Social Networking Websites

      Organizations Providing General Support

        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

        • The British Association of Dermatologists has a patient information leaflet about Disseminated superficial actinic porokeratosis.
        • 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.
          • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
          • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
          • PubMed is a searchable database of medical literature and lists journal articles that discuss Disseminated superficial actinic porokeratosis. Click on the link to view a sample search on this topic.

            Selected Full-Text Journal Articles


              1. Disseminated superficial actinic porokeratosis. DermNet NZ. April, 2017; https://www.dermnetnz.org/topics/disseminated-superficial-actinic-porokeratosis/.
              2. Kanitakis J. Disseminated superficial actinic porokeratosis. Orphanet. October, 2015; https://www.orpha.net/consor/cgi-bin/OC_Exp.php?lng=en&Expert=79152.
              3. Isabelle Touitou et. al. The expanding spectrum of rare monogenic autoinflammatory diseases. Orphanet Journal of Rare Diseases. 2013; 8:162:https://www.ojrd.com/content/8/1/162.
              4. Linda V Spencer. Porokeratosis. Medscape. August 7, 2017; https://emedicine.medscape.com/article/1059123-overview.
              5. Atzmony L, Lim YH, Hamilton C, Leventhal JS, Wagner A et al. Topical cholesterol/lovastatin for the treatment of porokeratosis: A pathogenesis-directed therapy. J Am Acad Dermatol. Jan 2020; 82(1):123-131. https://pubmed.ncbi.nlm.nih.gov/31449901.