[Urticarial vasculitis associated with essential thrombocythaemia progressing to myelofibrosis]

Abstract

Background: Urticarial vasculitis (UV) is a rare form of leukocytoclastic vasculitis in which skin lesions resemble urticaria. UV comprises hypocomplementemic and normocomplementemic subtypes. To date, only 4 cases of UV associated with myeloproliferative disorders have been described, including 3 cases with essential thrombocythaemia (ET) and one case with polycythaemia vera.

Patients and methods: We describe the case of a 59-year-old male patient with JAK2-positive TE and secondary myelofibrosis and who developed multiple urticarial papules persisting for more than 24hours. Skin biopsy showed perivascular neutrophilic infiltrate with margination of neutrophils in the lumen of vessels and some leukocytoclastic patterns, and with red cell extravasation consistent with UV. Treatment with ruxolitinib (a JAK2 inhibitor) induced transient and partial control of the haematological symptoms but did not prevent UV flare. Prednisolone 20mg once daily was added, with good clinical response.

Discussion and conclusion: To our knowledge, this is the fourth reported case of UV associated with ET and the first case associated with MF.

Keywords: Essential thrombocythaemia; Myelofibrosis; Myélofibrose; Ruxolitinib; Thrombocytémie essentielle; Urticarial vasculitis; Vascularite urticarienne.