{'fraction_non_alphanumeric': 0.04286387187941592, 'fraction_numerical': 0.024964672633066416, 'mean_word_length': 4.966292134831461, 'pattern_counts': {'":': 0, '<': 2, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
A case of leucocytoclastic vasculitis as a complication of IgG4‐related skin disease

IgG4-related disease (IgG4-RD) is a recently established immune-mediated systemic disorder characterized by tissue infiltration of IgG4-positive plasma cells and high serum levels of IgG4. The clinical manifestations of IgG4-RD involve a variety of organs and glands, including salivary, lacrimal and thyroid glands, and pancreas, kidney, lung and skin. Recently, Tokura et al. classified the skin manifestations of IgG4-RD into seven subtypes. We report a patient with a rare clinical manifestation of hypergammaglobulinaemic purpura as a skin lesion of IgG4-RD. A 54-year-old Japanese man presented to the Division of Gastroenterology of our clinic with a 1-month history of anorexia and weight loss (5.3 kg), and a 2week history of jaundice. Blood tests revealed a high serum level of conjugated bilirubin (7.4 mg/dL, normal range < 0.5 mg/dL), high serum IgG4 level of 1140 mg/dL (normal range 4.8–105 mg/dL), low serum complement levels and high level of antinuclear antibody (ANA) (1 : 1280; normal range < 1 : 40). Biopsy of the Vater papilla revealed lymphocyte and plasma cell infiltration of the mucosa, and additional immunohistochemistry revealed 22 IgG4-positive cells per high-power field (HPF) and 55.4% (31/56) IgG4+/ IgG+ plasma cells infiltrating the tissue (Fig. 1a,b). The diagnosis was IgG4-RD according to the Japanese comprehensive diagnostic criteria for IgG4-RD, and treatment was scheduled. Prior to treatment commencement, the patient was referred to our department for a consultation because of the appearance of multiple asymptomatic palpable purpuric papules on his legs (Fig. 2a). Tests for antineutrophilic cytoplasmic antibodies were negative. We suspected the palpable purpura as a manifestation of IgG4-RD, and took a skin biopsy. Histological examination reveled swelling of vessel walls in the papillary dermis, with nuclear dust that represented leucocytoclastic vasculitis (Fig. 2b). Direct immunofluorescence identified deposition of IgG, IgM and IgA in the walls of the small vessels of the upper