Although in 90% of patients there is no evidence of systemic involvement, sometimes urticaria pigmentosa
may be associated with ulcers, malabsorption, bone abnormalities hepatomegaly, splenomegaly, lymphadenopathy, peripheral blood abnormalities, elevated levels of plasma or urinary histamine or histamine metabolites, prostaglandin D2, and other metabolites in urine or plasma.2,15
Mastocytosis and atopy: a study of 33 patients with urticaria pigmentosa
. Allergy 1990; 45: 597-603.
Moss, "Urticaria pigmentosa
and acute lymphoblastic leukaemia," Journal of the Royal Society of Medicine, vol.
. Int J Dermatol 1997; 36:321-5.
Adult patients with systemic mastocytosis frequently, but not universally, have urticaria pigmentosa
skin lesions (10).
The pathogenic variation D816Y has been previously reported in a patient with acute myeloid leukemia with a background of SM and also in pediatric patients with urticaria pigmentosa
(6, 33, 37).
Mastocytosis represents a spectrum of disease ranging from urticaria pigmentosa
, an increase of dermal mast cells, to systemic mastocytosis involving bone marrow, skeleton, gastrointestinal canal, liver and spleen.
(orange to brown hyperpigmentation of the lesions, wheals are of smaller diameters, and Darier's sign is positive).
Based on the presence of a positive Darier's sign and the results of the skin biopsy (which showed increased mast cells), we diagnosed urticaria pigmentosa
(UP), which is the most common form of cutaneous mastocytosis.
Results: All patients had cutaneous mastocytosis, 19 patients had urticaria pigmentosa
and 2 patients had mastocytoma.
Mastocytosis may present with cutaneous mast cell accumulation (such as urticaria pigmentosa
), which is said to be present in up to 80% of cases (8) or with systemic manifestations such as flushing, diarrhoea, syncope or anaphylaxis.