Urticaria Pigmentosa

National Organization for Rare Disorders, Inc.

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  • Localized Infantile Mastocytosis
  • Mastocytosis, Infantile
  • Nettleship's, E. Disease Type I
  • Urticaria, Perstans Hemorrhagica
  • Xanthelasmoidea

Disorder Subdivisions

  • None

General Discussion

Urticaria pigmentosa is a rare skin disorder that is a localized (cutaneous) form of mastocytosis. Some clinicians suggest that urticaria pigmentosa is the childhood form of mastocytosis. Mast cells are specialized cells of connective tissue that release substances such as histamine (a chemical important in the inflammatory process) and heparin (an anti-clotting agent) when the body's alarm mechanism is set off. When mast cells cluster and multiply excessively (proliferate), histamine and heparin are released into the skin (mastocytosis). The characteristic skin lesions of urticaria pigmentosa appear in these areas. Urticaria pigmentosa is generally benign and is usually self-limited. The exact cause of the disease is not known, although some cases may be inherited.


The symptoms of urticaria pigmentosa include the appearance of reddish-brown itchy spots that look like freckles (pruritic macules) and/or bumps (papules) that appear on the skin. In rare cases, lesions may also develop in bones and/or other organs of the body. When skin lesions are touched and/or exposed to heat, they become smooth, slightly elevated, and redder or paler than the surrounding skin (urticarial). This reaction is known as Darier's sign. These areas, which are called wheals or more commonly hives, are usually extremely itchy and may change in size and shape within hours. Sometimes these wheals may resemble fluid-filled blisters (bullous).

Other uncommon symptoms of urticaria pigmentosa may include headache, a general feeling of ill health (malaise), flushing, abdominal pain, diarrhea, and/or an elevated heart rate (tachycardia). These symptoms are more characteristic of systemic mastocytosis. (For more information on mastocytosis, see the Related Disorders section of this report.)

In most cases, the symptoms of urticaria pigmentosa last for a few years and then resolve. Some individuals may have areas of lightly pigmented skin that remain for many years.


The exact cause of urticaria pigmentosa is not fully understood. Some cases occur for no apparent reason (sporadically), while others are thought to be inherited as an autosomal dominant genetic trait. However, not all children with the defective gene for urticaria pigmentosa will exhibit all of the characteristics of the gene (reduced penetrance).

Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.

Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.

Affected Populations

Urticaria pigmentosa is a rare disorder that affects males and females in equal numbers. The symptoms typically begin during the first year of life. Skin lesions generally disappear by adolescence. Urticaria pigmentosa occurs more frequently in children who also have allergies such as hay fever and/or asthma. Approximately 50 cases of the inherited form of urticaria pigmentosa have been reported in the medical literature.

Standard Therapies


The diagnosis of Urticaria pigmentosa is confirmed by a clinical evaluation and the microscopic examination of skin tissue samples. In some cases, laboratory testing may reveal elevated levels of histamine and a particular enzyme (mast cell tryptase protein) in the blood of affected individuals. Affected patients exhibit persistent, rather than transitory, levels of blood histamine and tryptase.


Treatment of urticaria pigmentosa is symptomatic and supportive. Steroid creams applied to the skin (topical steroids) may be useful for some children with this disease. Antihistamine drugs may also be given by mouth to help relieve itching.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government web site.

For information about clinical trials being conducted at the NIH Clinical Center in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:


People with urticaria pigmentosa have been treated experimentally with oral disodium cromoglycate, cimetidine (an H-2 antihistamine), or cimetidine/ketotifen combined with chlorpheniramine or propantheline. More study is needed to determine the long-term safety and effectiveness of these drugs and the various drug combinations for the treatment of urticaria pigmentosa.



Akin C. Metcalfe DD. Mastocytosis. In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:402.

Berkow R., ed. The Merck Manual-Home Edition. Whitehouse Station, NJ: Merck Research Laboratories; 1997:831.

Champion RH, Burton JL, Ebling FJG. Eds. Textbook of Dermatology. 5th ed. Blackwell Scientific Publications. London, UK; 1992:2067-71.


Escribano L, Akin C, Castells M, et al. Mastocytosis: current concepts in diagnosis and treatment. Ann Hematol. 2002;81:677-90.

Gupta R, Bain BJ, Knight CL. Cytogenic and molecular genetic abnormalities in systemic mastocytosis. Acta Haematol. 2002;107:123-28.

Valent P, Horny HP, Escribano L, et al. Diagnostic criteria and classification of mastocytosis: a consensus proposal. Leuk Res. 2001;25:603-25.

Marone G, Spadaro G, Granata F, et al. Treatment of mastocytosis: pharmacologic basis and current concepts. Leuk Res. 2001;25:583-94.

Li CY. Diagnosis of mastocytosis: value of cytochemistry and immunohistochemistry. Leuk Res. 2001;25:537-41.

Wolff K, Komar M, Petzelbauer P. Clinical and histopathological aspects of cutaneous mastocytosis. Leuk Res. 2001;25:519-28.

Bedlow AJ, Gharrie S, Harland CC. The treatment of urticaria pigmentosa with frequency-doubled Q-switch Nd:YAG laser. J Cutan Laser Ther. 2000;2:45-47.


McKusick VA, Ed. Online Mendelian Inheritance in Man (OMIM). The Johns Hopkins University. Entry Number; 154800: Last Edit Date; 12/6/1999.

Lehrer M. Urticaria pigmentosa. Medlineplus. Medical Encyclopedia. Update Date 8/7/2001. 3pp.


Mastocytosis. NIAID Fact Sheet. January 2002. 3pp.


Soignee M. Urticaria Pigmentosa. nd. 2pp.


Akin C. Mastocytosis in Children - The Basics for Parents. Mastocytosis Pediatric Information and Parent Support. Various dates, various lengths.


Diagnosis and Treatment of Mastocytosis.


What are mast cells? [Etc.]


Urticaria pigmentosa (mastocytosis) - Information for Parents. nd. 3pp.


Lehrer M. Urticaria Pigmentosa Information. Review Date: 8/7/2001. Various lengths.







Urticaria pigmentosa. ENLmedical. Medical Encyclopedia. nd. 5pp.



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For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders, Inc.® (NORD). Cigna members can access the complete report by logging into myCigna.com. For non-Cigna members, a copy of the complete report can be obtained for a small fee by visiting the NORD website. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational treatments (if available), and references from medical literature. For a full-text version of this topic, see http://www.rarediseases.org/search/rdblist.html.