A 48 year old male patient presented with maculopapular rash, pruritus, peptic ulcer disease and attacks of headache and vertigo. Rubbing of the cutaneous lesions led to urticarial whealing which is indicative of abnormal mast cell proliferation in the cutis. Histologic evidence of abnormal mast cell proliferation in biopsy specimens of skin and bone marrow led to the diagnosis of systemic mastocytosis. Treatment with H1 and H2 receptor antagonists was started.