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urticaria pigmentosa (UP)
A generalized cutaneous mastocytosis.
Epidemiology: onset between birth & 2 years of age.
Clinical manifestations:
1) slightly tan macules to slightly raised papules/nodules
2) dermatographism
3) bright red flushing
a) spontaneous
b) following rubbing of skin
c) ingestion of alcohol or other mast-cell degranulating agents
4) widespread symmetric distribution
5) a few to > 100 lesions
Differential diagnosis:
1) Histiocytosis
2) secondary syphilis
3) sarcoid
4) histiocytoma
5) non-X histiocytosis
Related
Darier's sign
dermatographism
General
mastocytosis
References
Color Atlas & Synopsis of Clinical Dermatology, Common
& Serious Diseases, 3rd ed, Fitzpatrick et al, McGraw Hill, NY,
1997, pg 718, 562-65