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A premature female Dirofilaria species, subsequently identified as Dirofilaria repens by its morphological features and mitochondrial 12S ribosomal RNA (12S rRNA) gene sequence, was removed from a subcutaneous nodule of the right temporal region of the head in a Japanese woman 2 years after she noticed swelling of her left calf following an insect sting during a tour to Europe; headache symptoms were noticed a few months later. The sequences of the mitochondrial 12S rRNA and cytochrome c oxidase subunit I genes from the organism were almost identical to those of sequences AM779772 (100% homology, 337/337) and AM749233 (99.8% homology, 536/537) of D. repens isolated from humans in Italy. However, the phylogenetic position of the 18S rRNA-internal transcribed spacer 1-5.8S rRNA region was in the same cluster as that of sequence JX290195 of Dirofilaria sp. “hongkongensis” (96.7% homology, 348/360), which was recently reported from Hong Kong as a novel Dirofilaria species. Information on regional genetic variation in D. repens isolated from animals and humans remains scarce. We report the detailed genetic features of this filaria as a reference isolate from a specific endemic area, to enrich the genetic database of D. repens.

A case of a 7-year-old girl with microscopic polyangiitis (MPA) with a skin eruption characterized by maculopapular, erythematous and purpuric lesions on the face, elbows, and knees is presented. Anti-neutrophil cytoplasmic autoantibodies (ANCA) with myeloperoxidase specificity (MPO-ANCA) were identified. Chest X-ray and computed tomography scan revealed diffuse infiltrates in both lung fields, suggesting alveolar hemorrhage. Microscopic hematuria was detected but a renal biopsy showed no abnormalities. Histological  examination  of a skin biopsy from a  purpuric papule showed leukocytoclastic vasculitis of the small vessels in the entire dermis. The patient was treated with prednisolone and mizoribine, resulting in an improvement in the skin lesions except for those on the knee.

Autoinflammatory diseases (AIDs) characterized by recurrent episodes of localized or systemic inflammation are disorders of the innate immune system. Skin lesions are commonly found in AIDs and cutaneous vasculitis can coexist with AIDs and even present as the most striking feature. This review aims to focus on the frequent cutaneous vasculitis association in three monogenic AIDs including familial Mediterranean fever (FMF), deficiency of adenosine deaminase type 2 (DADA2), and the recently identified adult‐onset VEXAS (vacuoles, E1 enzyme, X‐linked, autoinflammatory, somatic) syndrome. Cutaneous vasculitis in FMF is characterized by: (1) small‐vessel vasculitis similar to IgA vasculitis with palpable purpura but increased intussusception complication and less vascular IgA deposit, and (2) cutaneous arteritis–like vasculitis presenting as subcutaneous nodules most often with higher glomerular involvement. DADA2 has a wide spectrum of clinical presentations ranging from fatal systemic vasculitis with multiple strokes, especially in pediatric patients, to limited cutaneous disease in middle‐aged patients. DADA2 shares similar clinical and histopathological features with polyarteritis nodosa (PAN). As a result, DADA2 is commonly initially misdiagnosed as childhood PAN. Livedo racemosa reveals the most common cutaneous manifestation of cutaneous vasculitis in patients with DADA2. VEXAS syndrome is a life‐threatening disease. A diagnosis of VEXAS syndrome should be strongly considered or could be made in patients with skin lesions characterized by Sweet syndrome–like eruption, livedo racemosa, concomitant relapsing polychondritis, deep venous thrombosis, pulmonary involvement, and progressive hematologic abnormalities such as myelodysplastic syndrome with a unique finding of cytoplasmic vacuoles in myeloid and erythroid precursor cells from bone marrow aspirate smear. As skin involvement is common in AIDs and may present as the most frequent manifestation, especially in DADA2 (70% to 90%) and VEXAS syndrome (83% to 91%), dermatologists play a crucial role in contributing to the early diagnosis of these AIDs with early initiation of the appropriate therapy to avoid progressing fatal outcomes. [ABSTRACT FROM AUTHOR]

Previous studies have shown that erythema nodosum-like lesions in patients with Behçet's disease show cutaneous vasculitis of either phlebitis or dermal venulitis. To analyse the clinicopathological characteristics of superficial thrombophlebitis as well as cutaneous venulitis in Behçet's disease. We re-evaluated the histopathological features of superficial thrombophlebitis in patients with Behçet's disease. Five patients, one man and four women, developed superficial thrombophlebitis on the lower extremities. Two of the patients had vascular Behçet's disease, both also developed deep vein thrombosis. One patient had intestinal Behçet's disease. In all cases, venulitis in the overlying lower dermis or adjacent subcutis spreading from the main affected subcutaneous thrombophlebitis lesions was observed. Both neutrophilic venulitis (n = 2) and lymphocytic venulitis (n = 3) were observed at the same depth level or upper/lower location of the thrombophlebitis in the same specimens. In addition, concurrent venulitis with fibrin thrombus and fibrinoid necrosis was observed in one case, suggesting that fibrin thrombus affected both venules and muscular veins. By contrast, arteritis or arteriolitis at the same depth level was not observed. Our results showed histopathological features of coexistent thrombophlebitis and venulitis without involvement of either arteries or arterioles in the biopsied specimens of superficial thrombophlebitis. Further studies are necessary to support that those unique histopathological findings are the characteristic features and significant diagnostic indicators of Behçet's disease. [ABSTRACT FROM AUTHOR]