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Urticaria pigmentosa in Child
Other Resources UpToDate PubMed

Urticaria pigmentosa in Child

Contributors: Andrew R. Blundell MSc, Elena B. Hawryluk MD, PhD, Belinda Tan MD, PhD, Susan Burgin MD
Other Resources UpToDate PubMed


Mastocytosis is a term broadly referring to tissue mast cell hyperplasia. According to the World Health Organization (WHO) classification, cutaneous and systemic forms of mastocytosis are distinguished. Mastocytosis most commonly manifests as cutaneous disease in childhood, which is further subdivided into urticaria pigmentosa (UP, also known as maculopapular cutaneous mastocytosis), localized mastocytoma of skin, and diffuse cutaneous mastocytosis. Cutaneous mastocytosis in childhood has an excellent prognosis, with many cases remitting during puberty. Severe presentations may be persistent into adulthood (see mastocytosis in adults).

UP is the most common form of cutaneous mastocytosis in children. UP presents with few to many persistent, pink and brown macules and papules that urticate or wheal with thermal, mechanical, or chemical stimuli. Up to 25% of pediatric UP patients develop gastrointestinal symptoms. Fever, night sweats, malaise, epigastric tenderness, weight loss, flushing, diarrhea, syncope, bronchospasm, and problems with cognition signal possible systemic involvement.

Somatic c-kit mutations and other mast cell immunophenotypic alterations have been implicated in the pathophysiology of mastocytosis.

When triggered, mast cells release mediators such as histamine prostaglandins, eicosanoids, heparin, leukotrienes, cytokines, and proteases, causing patients with UP to become symptomatic. Triggers can include heat or temperature changes, trauma to skin lesions, insect stings, psychological stress, anxiety, and certain drugs such as NSAIDs, anesthetics, opioids, muscle relaxants, antibiotics, and iodinated radiocontrast agents.

UP can present at any time, but it commonly presents within the first weeks to months of life and can be expected to spontaneously involute by adolescence. There is no sex or race predilection. Partial to complete regression occurs in most children, as opposed to adults, in whom UP tends to persist.


Q82.2 – Mastocytosis

78745000 – Urticaria pigmentosa

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Diagnostic Pearls

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Differential Diagnosis & Pitfalls

  • Mastocytoma – One or a few (fewer than 4, by definition) round or ovoid papules, plaques, or nodules are seen, typically with onset in early infancy.
  • Diffuse cutaneous mastocytosis presents with indurated, thickened skin, and numerous confluent papules are present. Systemic involvement is more common.
  • Juvenile xanthogranuloma has brown papules but will have a negative Darier sign.
  • Multiple Spitz nevus
  • Bullous impetigo

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Drug Reaction Data

Below is a list of drugs with literature evidence indicating an adverse association with this diagnosis. The list is continually updated through ongoing research and new medication approvals. Click on Citations to sort by number of citations or click on Medication to sort the medications alphabetically.

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Last Reviewed:03/23/2020
Last Updated:03/26/2020
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Urticaria pigmentosa in Child
A medical illustration showing key findings of Urticaria pigmentosa : Blisters, Peau d'orange, Primarily truncal distribution, Widespread distribution, Pruritus
Clinical image of Urticaria pigmentosa - imageId=1316038. Click to open in gallery.  caption: 'Myriad red-brown macules and papules on the face, neck, and back.'
Myriad red-brown macules and papules on the face, neck, and back.
Copyright © 2024 VisualDx®. All rights reserved.