Differential Diagnosis

  • Urticaria pigmentosa
  • Bullous impetigo
  • Atopic dermatitis
  • Psoriasis


This patient was diagnosed with urticaria pigmentosa, a form of cutaneous mastocytosis in which mast cells accumulate in the skin, causing the characteristic skin lesions seen here.



  • Urticaria pigmentosa presents within the first week-to-months of life, though involution can occur in early childhood or last until puberty
  • Bronchospasm, as well as flushing, diarrhea, and syncope can all occur
  • Unlike adult forms of mastocytosis, there is rarely internal organ involvement in children


Pearls for Urgent Care Management and Considerations for Transfer

  • There is no “cure,” per se, for urticaria pigmentosa, though antihistamines can relieve itching and flushing. Other treatments include:
    • Topical corticosteroids
    • Hydrocolloid dressings
    • Fluocinolone acetenoide
  • Parents of younger children should try to discourage scratching or rubbing of itchy skin, as doing so could spur a stronger reaction


Acknowledgment: Images courtesy of VisualDx.

An 18-Month-Old with an Itchy Rash and Wheezing
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