title: Hyperpigmented cutaneous lesions that flare-up with scratching: Darier's sign.
abstract: We present the case of a 40-year-old male with a past medical history of urticaria pigmentosa (UP) who presented for consultation to the Allergy clinic for an opinion of systemic mastocytosis. Previous workups included elevated serum tryptase level, UP on skin biopsy and an increased number of CD117-positive/CD25-positive mast cells on bone marrow biopsy. This case emphasizes the importance of physical findings such as Darier's sign in patients with hyperpigmented lesions, which virtually supports the diagnosis UP, raises the suspicion for systemic mastocytosis and guides further diagnostic evaluation. This case also outlines the management of systemic mastocytosis.
authors.affiliation: Department of Internal Medicine , Medicine Institute, Cleveland Clinic , Cleveland, OH , USA.
authors.forename: Lyda B
authors.initials: LB
authors.lastname: Cuervo-Pardo
authors.affiliation: Department of Allergy and Clinical Immunology , Respiratory Institute, Cleveland Clinic , Cleveland, OH , USA.
authors.forename: Alexei
authors.initials: A
authors.lastname: Gonzalez-Estrada
authors.affiliation: Robert J. Tomsich Pathology and Laboratory Medicine Institute, Cleveland Clinic Foundation , Cleveland, OH , USA.
authors.forename: Sory J
authors.initials: SJ
authors.lastname: Ruiz
authors.affiliation: Department of Allergy and Clinical Immunology , Respiratory Institute, Cleveland Clinic , Cleveland, OH , USA.
authors.forename: Lily C
authors.initials: LC
authors.lastname: Pien