Rare Infectious Disease News

Disease Profile

Pityriasis rotunda

Prevalence
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.

Unknown

Age of onset

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ICD-10

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Inheritance

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

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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

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X-linked
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.

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

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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.

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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.

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Not applicable

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Summary

Pityriasis rotunda is a rare skin disease characterized by round, scaly, pigmented patches that mainly occur on the trunk, arms and legs. There are two types of pityriasis rotunda. Type 1 is seen mainly in East/Southeast Asian and South African individuals older than 60 years, and is often associated with internal disease or malignancy (cancer). Type 2 occurs in lighter skinned individuals younger than 40 years, and often in several members of the same family. Type 2 pityriasis rotunda is not associated with internal disease or malignancy. The cause of pityriasis rotunda is unknown, but it may be a variant of ichthyosis vulgaris. Type 1 most often occurs with liver and stomach cancer.[1]

Symptoms

The lesions that result from pityriasis rotunda usually do not cause specific symptoms and/or lead to serious complications. However, pityriasis rotunda can occur with serious underlying systemic diseases and cancers, such as stomach cancer and liver cancer.[2]

Affected individuals usually have several lesions, ranging from 4 to 80, that are commonly found on the buttocks, thighs, abdomen, trunk, and upper and lower extremities. The patches are often almost perfectly circular and sharply defined with dry ichthyosis-like scaling. The lesions range between 0.5 and 20 cm in diameter and are generally isolated, although merging of lesions can create a polycylic shape. Colors range from pink to light-brown. Once the lesions develop, they usually remain unchanged throughout life unless the underlying internal disease or malignancy is treated, in which case, they resolve or improve.[1][2]

There appear to be two types of pityriasis rotunda. Type 1 pityriasis rotunda usually affects South African and East/Southeast Asian individuals older than 60 years who tend to have associated malignancies (cancers) or systemic disease. The lesions found in those with type 1 are usually darker (hyperpigmented) than the surrounding skin; and other family members are not affected. Type 2 affects people with lighter skin who are younger than 40 years. These individuals do not have any associated malignancy or systemic diseases, but have multiple lesions that are lighter (hypopigmented) than the surrounding skin. Type 2 also tends to run in families.[2]

Cause

The exact cause of pityriasis rotunda is unknown, but some researchers believe that it may be a variant of ichthyosis vulgaris.[1][2] Other researchers believe that pityriasis rotunda is caused by malnutrition, but this is not universally accepted. The presence of systemic disease, which is characteristic of type 1 pityriasis rotunda, appears to be most common in South African and Japanese individuals, but is less common among Caucasians.[2] Type 1 most often occurs with stomach cancer and liver cancer. Other conditions that type 1 pityriasis rotunda has been associated with include:[1][2]

It has been proposed that type 2 pityriasis rotunda, which is typically inherited in families and seen in lighter skinned individuals, is inherited in an autosomal dominant manner.[1]

Treatment

There is no specific treatment for pityriasis rotunda. People diagnosed with this condition usually need to undergo medical and physical examinations and have appropriate laboratory and radiographic tests to check for internal disease or malignancies. The lesions usually improve or resolve with treatment of the underlying internal disease or malignancy. Symptomatic treatment of lesions using topical retinoids, salicylic acid ointment, and lactic acid lotion has been used.[1] However, the lesions can be resistant to therapy.[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 Pityriasis rotunda. Click on the link to view a sample search on this topic.

References

  1. Pityriasis rotunda. DermNet NZ. December 29, 2013; https://dermnetnz.org/scaly/pityriasis-rotunda.html. Accessed 6/3/2014.
  2. Rao J. Pityriasis rotunda. Medscape Reference: Treatment & Management. March 3, 2014; https://emedicine.medscape.com/article/1107624-treatment. Accessed 6/3/2014.

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