Division of Dermatology, Saiseikai Izuo Hospital, 3-4-5 Kitamura, Taisho-ku, Osaka 551-0032, Japan.
Department of Dermatology, Kurume University School of Medicine and Kurume University Institute of Cutaneous Cell Biology, 67 Asahimachi, Kurume, Fukuoka 830-0011, Japan.
Eur J Dermatol. 2013 May-Jun;23(3):362-5. doi: 10.1684/ejd.2013.2046.
IgA pemphigus is a rare variant of pemphigus. IgA pemphigus is subdivided into intraepidermal neutrophilic IgA dermatosis-type (IEN-type), whose target antigen is still an enigma, and subcorneal pustular dermatosis-type, whose target antigen is desmocollin 1 (Dsc1). We report a 56-year-old Japanese male with IgA pemphigus showing atypical erythema. One month after erythema developed, the patient visited his private physician, and was tentatively diagnosed as having erythema multiforme. The patient had been intermittently treated with a low dose of oral prednisolone for a year without benefit before visiting our hospital. Clinical examination revealed irregularly-shaped and partially edematous erythema over the trunk and extremities without mucosal involvement. Neither bullae nor pustules were seen during the course. Direct immunofluorescence showed IgA deposition on cell surfaces of keratinocytes in the upper two thirds of the epidermis. Indirect immunofluorescence of monkey esophagus sections revealed IgA and IgG anti-cell surface antibodies. Our new enzyme-linked immunosorbent assays using eukaryotic recombinant proteins of human Dsc 1-3 detected IgA antibodies to Dsc1 and Dsc2. Although no apparent bullae were observed, the diagnosis of IgA pemphigus was made. Prednisolone 30 mg daily was required to control erythematous lesions. Although the pathomechanism for the unique skin lesion is unknown, the possibility that IgA pemphigus has a prodromal phase and that early administration of low dose prednisolone suppressed the development of pustules or bullae were considered.
IgA 天疱疮是天疱疮的一种罕见变体。IgA 天疱疮分为表皮内中性粒细胞 IgA 皮肤病型（IEN 型），其靶抗原仍是个谜，以及棘层下脓疱性皮病型，其靶抗原是桥粒芯糖蛋白 1（Dsc1）。我们报告了一例 56 岁日本男性患有 IgA 天疱疮，表现为非典型红斑。红斑出现一个月后，患者就诊于私人医生，并被初步诊断为多形红斑。患者曾间断接受低剂量口服泼尼松治疗一年，但未见改善，随后就诊于我院。临床检查显示躯干和四肢不规则形状和部分水肿性红斑，无黏膜受累。在整个病程中未见水疱或脓疱。直接免疫荧光显示 IgA 沉积在上表皮的 2/3 处的角质形成细胞表面。猴食管切片间接免疫荧光显示 IgA 和 IgG 抗细胞表面抗体。我们使用人 Dsc1-3 的真核重组蛋白新的酶联免疫吸附试验检测到针对 Dsc1 和 Dsc2 的 IgA 抗体。尽管未观察到明显的水疱，但仍诊断为 IgA 天疱疮。需要每日口服泼尼松 30mg 来控制红斑病变。虽然独特皮肤病变的发病机制尚不清楚，但考虑到 IgA 天疱疮可能有前驱期，早期给予低剂量泼尼松可抑制脓疱或水疱的发生。
