Clinical and laboratory findings characterizing the need for systemic corticosteroids and nonsteroidal systemic therapies, and the predicted outcomes in cutaneous polyarteritis nodosa: A single-centre retrospective analysis.

BACKGROUND: Cutaneous polyarteritis nodosa (cPN) is a necrotizing arteritis of medium-sized vessels limited to the skin. Because of its rarity and the diversity of its clinical manifestations, there is no consensus treatment. Moreover, there are no established indicators that predict disease severity or its outcome. OBJECTIVES: To investigate clinico-laboratory features that predict patients requiring systemic therapy, including corticosteroids, to control the disease activity. METHODS: Thirty-six cPN patients who had not received systemic corticosteroids at the initial visit were retrospectively analysed by correlating the treatment and its response with clinico-laboratory findings. RESULTS: The major medications administered were antiplatelet agents (63.9%), vasodilators (38.9%), and prednisolone (PSL) (36.1%). In all, 23 cases achieved remission without PSL; 5 were managed with compression therapy alone or even observation; 18 received antiplatelet monotherapy or combined with vasodilator/dapsone; 13 required PSL; 10 achieved remission with PSL monotherapy or PSL and single/multiple medications and 3 with PSL and multiple drugs failed to achieve remission and underwent limb amputation. There were more skin ulcers and an elevated peripheral white blood cell (WBC) count and erythrocyte sedimentation rate (ESR) before corticosteroid induction in patients requiring PSL. Three cases with treatment failure had a markedly elevated ESR (>50). CONCLUSIONS: More than half of cPN can achieve remission without corticosteroids; an elevated WBC and the presence of skin ulcers predict the need for PSL; a high ESR before corticosteroid induction predicts treatment resistance, even with PSL.

Reappraisal of histopathology of cutaneous polyarteritis nodosa.

BACKGROUND: There is controversy on whether lymphocytic thrombophilic arteritis (LTA) and macular arteritis (MA) are a different entity from cutaneous polyarteritis nodosa (C-PAN). OBJECTIVE: To evaluate the controversy on LTA/MA by examining the morphologic changes during the dynamic inflammatory process. MATERIALS AND METHODS: A clinical and histopathological investigation of 46 biopsy specimens from 21 histopathologically proven C-PAN patients at our hospital was performed. RESULTS: Most of the biopsy findings revealed arteritis in the subacute and reparative stages. Coexistence of different stages was found in over half of the specimens. Two biopsy specimens consistent with LTA/MA showed coexisting histologically proven (subacute stage) C-PAN in other lesions. Analyses of the longitudinal sections showed focal and segmental arteritis. Patients overall improved well with compression stockings, anti-inflammatory agents, a prostaglandin analog and antiplatelet agents. Currently, three patients are medication free and only require compression stockings. CONCLUSION: LTA/MA seems to be part of the spectrum of C-PAN. The vasculitic lesions of C-PAN are segmental and focal, and coexist in different stages. As the chronic stage of C-PAN can be mistaken as LTA/MA, it is necessary to perform multiple biopsies, serial sections and analyses of longitudinal sections to confirm the main finding of vasculitis.

Microbiota-Independent Spontaneous Dermatitis Associated with Increased Sebaceous Lipid Production in Tmem79-Deficient Mice.

TMEM79 is a predisposing gene for atopic dermatitis. Tmem79-deficient mice develop spontaneous dermatitis in a biphasic pattern. The first-phase dermatitis is unique because it occurs independent of microbiota status, whereas the second-phase dermatitis is microbiota dependent. In this study, we sought to identify the key factors mediating the development of first-phase dermatitis. Structural analysis showed that sebaceous gland hyperplasia started from first-phase dermatitis. Longitudinal RNA sequencing analysis revealed significant activation of fatty acid lipid metabolism pathways in first-phase dermatitis, whereas T helper 17‒based immune response genes were highly expressed in second-phase dermatitis. Quantitative RT-PCR analysis revealed that genes involved in fatty acid elongation and sebocyte differentiation were upregulated in first-phase dermatitis. The results of thin-layer chromatography supported these findings with an increased abundance of wax esters, cholesterol esters, and fatty alcohols in hair lipids. Further gas chromatography-tandem mass spectrometry analysis showed an increase in total fatty acid production, including that of elongated C20-24 saturated and C18-24 monounsaturated fatty acids. Collectively, these results suggest that aberrant production of sebaceous long-chain fatty acids is associated with microbiota-independent dermatitis. Further investigation of Tmem79-deficient mice may clarify the role of certain fatty acids in dermatitis.