Neutrophilic dermatosis of the dorsal hands: pustular vasculitis revisited.

An entity termed "pustular vasculitis of the hands" was recently described. Patients with this condition presented with low-grade fevers and erythematous plaques, pustules, and bullae limited to the dorsal hands and fingers, which were characterized histologically by a dense neutrophilic infiltrate and leukocytoclastic vasculitis. We describe patients with a similar clinical presentation, but who lacked vasculitis on biopsy findings. We describe 3 otherwise asymptomatic patients with hemorrhagic bullae, plaques, and pustules solely on the dorsal hands. Biopsy specimens showed a neutrophilic infiltrate and leukocytoclasis, but no necrotizing vasculitis, and were reminiscent of Sweet's neutrophilic dermatoses. In our patients, corticosteroids or dapsone led to clearing of the lesions, and small maintenance doses of dapsone prevented their recurrence. Our 3 patients had clinical lesions similar to those termed pustular vasculitis of the hands, but which lacked leukocytoclastic vasculitis on biopsy findings. Because of histologic findings and a therapeutic response more characteristic of Sweet's syndrome, we propose the term neutrophilic dermatosis of the dorsal hands. In addition, low-dose dapsone is proposed as a possible first-line therapy in this condition, especially in those with recurrent disease.

Leukocytoclastic vasculitis due to etanercept.

Recently etanercept, a soluble recombinant tumor necrosis factor receptor:Fc fusion protein, became available to treat patients with rheumatoid arthritis (RA). Among adverse reactions are cutaneous side effects, which occur in about 5% of patients. These have included mostly injection site reactions as well as urticarial reactions. We describe the first case of leukocytoclastic vasculitis associated with the use of etanercept in a patient with severe, deforming RA previously unresponsive to multiple therapies. Discontinuation of the drug led to complete resolution of the vasculitis.

Cytological alterations in dermal dendrocytes in vitro: evidence for transformation to a non-dendritic phenotype.

Dermal dendrocytes (DDs) are bone marrow-derived cells which are abundant in normal human and murine dermis, where they are closely associated with mast cells in the perivascular space. The biological role of DDs remains enigmatic. DDs express coagulation factor XIIIa and the recently described von Willebrand factor receptor, GPIb alpha, potentially indicating a function in tissue repair and haemostasis, although participation in antigen presentation is also speculated. In healing wounds and 'fibrohistiocytic' tumours, such as dermatofibromas, DDs are often associated with non-dendritic histiocytes, some of which also express factor XIIIa (FXIIIa). We have utilized human skin organ culture to examine the effects of various biological mediators on cytological characteristics of DDs. It was found that by 24 h in organ culture, immunoreactive DDs begin to lose their dendritic shape, assuming more rounded contours. This phenomenon was accentuated by mast cell degranulation; was independent of the nature of mast cell secretagogue; and could not be reproduced by recombinant tumour necrosis factor-alpha, a cytokine known to increase FXIIIa expression in DDs. Like their dendritic precursors, non-dendritic cells expressed variable FXIIIa, CD34 and CD68 and did not express CD1a or CD45. By ultrastructure, non-dendritic cells that develop in vitro resembled non-degenerating monocytes containing occasional primary lysosomes and lipid inclusions, and like DDs, expressed fibronexus-like plaques on the cell membrane. Transition of DDs from dendritic to non-dendritic cells as a consequence of specific microenvironmental influences may provide insight into the frequent concurrence of these two cytological types in fibrohistiocytic tissue reactions and neoplasia.