[Cutaneous plasmacytosis with Darier's sign in a woman of European origin]. / Plasmocytose cutanée avec signe de Darier chez une femme d'ascendance européenne.

INTRODUCTION: Cutaneous plasmacytosis is a rare skin condition first described in 1976 and it is seen mainly in patients of Asian descent. Patients usually present with multiple reddish-brown macules and nodules chiefly on the trunk and face, with clusters of well-differentiated plasma cells in the dermis. The aetiopathogenesis and nosological features of this entity remain obscure. We report herein a case of cutaneous plasmacytosis in a European middle-aged woman with presence of Darier's sign. PATIENTS AND METHODS: A 56-year-old woman of European descent presented with asymptomatic hyperpigmented patches affecting the dorsal aspect of her trunk for at least two years. Darier's sign was present in some episodes. Cutaneous biopsy showed a moderately dense interstitial and perivascular infiltrate containing numerous well-differentiated mature plasma cells affecting the entire dermal surface. Kappa and lambda immunochemistry demonstrated polyclonal plasma cell infiltrates with absence of light-chain restriction. Immunohistochemical examination was negative for HHV-8 and Treponema pallidum spirochetes. Laboratory findings revealed hypergammaglobulinaemia with no monoclonal bands being detected on immunofixation. A diagnosis of cutaneous plasmacytosis was made. In the absence of systemic involvement initial management consisted of clinical surveillance. DISCUSSION: The characteristic clinico-pathological features of CP allowed diagnosis of this skin condition in our patient, although it is very rarely reported in patients of European descent. The main differential diagnoses were ruled out, namely plasmacytic infiltrates related to infections and marginal B-cell lymphoma.

[Cutaneo-systemic necrotizing vasculitis occurring during desensitization]. / Vascularite nécrosante cutanéo-systémique survenue en cours de désensibilisation.

The authors report a case of cutaneo-systemic necrotizing vasculitis, predominantly affecting the skin and digestive tract, observed in an asthmatic patient undergoing desensitization with Graminaceae pollen extract and mite-enriched house dust. Vasculitis developed 22 months after the first injections, became autonomous after the end of treatment and responded well to systemic corticosteroid therapy in daily doses of 1 mg/kg. The patient was followed up for 8 months during which the vasculitis did not recur, despite reduction in steroid dosage. Reports of necrotizing vasculitis occurring during desensitization seem to be very rare. They raise the problem of whether specific immunotherapy plays a role in the pathogenesis of vasculitis. Most of the characteristics that emerged from the cases previously published are concordant with those found in our patient: the interval between the first injections and the initial symptoms varied from 45 days to 8 years; in every case the condition followed its own course after the injections were discontinued; most patients were being desensitized to several allergens; the cutaneous symptoms were pronounced, eosinophilia was moderate and hepatitis B serology was constantly negative. The few prospective studies aimed at determining, by different methods, the levels of circulating immune complexes (CIC) have given conflicting results. Atopic subjects have high CIC levels, but these do not seem to be influenced by desensitization. The nature of the CIC remains unknown, and the various suggestions put forward (cross-reaction between blocking IgG and auto-antibodies, CIC [blocking IgG, anti-idiotype antibodies]) require confirmation, although the hypothesis of pathogenic CIC (allergen, blocking IgG) is unlikely to be correct.(ABSTRACT TRUNCATED AT 250 WORDS)