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Disease Profile

Diffuse cutaneous mastocytosis

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.

<1 / 1 000 000

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)

DCM; Diffuse cutaneous maculopapulous mastocytosis


The following summary is from Orphanet, a European reference portal for information on rare diseases and orphan drugs.

Orpha Number: 79456

Diffuse cutaneous mastocytosis (DCM) is a rare form of cutaneous mastocytosis (CM; see this term) characterized by generalized erythroderma, various degrees of blistering, skin with a ''peau d'orange'' appearance and the accumulation of mast cells in the skin. At least two DCM variants are recognized, one with extreme blistering (Bullous DCM; see this term) and one with infiltrations (Pseudoxanthomatous DCM; see this term).

DCM accounts for around 1-2% of all cases of CM and almost exclusively presents during infancy, mainly in the neonatal period. Less than 30 cases of neonatal onset DCM have been described in the literature so far.

Clinical description
The majority of patients present with generalized erythroderma with a reddish to brown-orange discoloration and extensive bullae. The blisters may become hemorrhagic, may be grouped or linear, and are usually located on the trunk, extremities or scalp. The bullous lesions typically resolve by 3-5 years of age. A small number of patients have been reported with yellow-orange infiltrated and xanthogranuloma-like abnormalities as the presenting feature of DCM (Pseudoxanthomatous DCM). Over time, the skin becomes thickened and has a doughy consistency. Other cutaneous manifestations may include pruritus, urticaria, a positive Darier's sign and marked dermographism. Systemic symptoms (including flushing, hypotension, severe anaphylaxis, hepatomegaly, diarrhea and gastrointestinal bleeding) appear to be more common in DCM than in other forms of CM with systemic symptoms.

DCM generally occurs sporadically but a few familial cases have been reported. Mutations in the KIT gene (4q11-q12) have been identified in patients with some forms of mastocytosis and mutations in this gene have been identified in a few patients with DCM.

Diagnostic methods
Diagnosis may be suspected on the basis of the clinical findings and can be confirmed by histological examination using mast cell stains (Giemsa and toluidine blue) or immunohistochemical staining for tryptase or kit. Measurements of serum tryptase and urinary N-methylhistamine levels may also be useful for diagnosis and follow-up.

Differential diagnosis
For patients presenting with widespread bullous lesions the differential diagnosis should include bullous congenital ichthyosiform erythroderma, early-onset forms of epidermolysis bullosa, Poikiloderma of Kindler (see these terms) and staphylococcal scalded skin syndrome.

Management and treatment
Treatment is symptomatic with administration of antihistamines (H1 and H2 in cases with gastrointestinal symptoms), topical steroids and mast cell membrane stabilizers. Factors that trigger mast cell degradation (non-steroidal anti-inflammatory drugs, physical stimuli, emotional stress, insect venom and certain foods) should be avoided. Oral steroid treatment and photochemotherapy with UVA therapy may be of benefit but should only be used in infancy in severe cases that are refractory to alternative treatment options. Close follow-up is required for early detection and management of systemic symptoms.

Although spontaneous resolution of the bullous lesions occurs before 5 years of age in most DCM patients, the prognosis is variable: DCM is associated with an increased risk of systemic involvement with life-threatening manifestations (gastrointestinal bleeding, anaphylaxis etc.). The association of DCM with mast cell leukemia has been reported in a few patients and persistence of DCM into adult life with transformation to indolent systemic mastocytosis has been described.

Visit the Orphanet disease page for more resources.


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
Abnormal blistering of the skin
Blistering, generalized

[ more ]

Cutaneous mastocytosis
30%-79% of people have these symptoms
Abnormality of skin pigmentation
Abnormal pigmentation
Abnormal skin color
Abnormal skin pigmentation
Abnormality of pigmentation
Pigmentary changes
Pigmentary skin changes
Pigmentation anomaly

[ more ]

Dermatographic urticaria
Low blood pressure
Itchy skin
Skin itching

[ more ]

Thickened skin
Thick skin
5%-29% of people have these symptoms
Anaphylactic shock
Gastrointestinal hemorrhage
Gastrointestinal bleeding
Enlarged liver
Intestinal malabsorption

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

In-Depth Information

  • 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.