我们报道了一例血清阴性的肌无力性皮肌炎（SADM）病例。应考虑这种临床实体在有反复出现的疼痛性红斑皮肤表现和需要密切监测神经病变和恶性肿瘤发展的患者鉴别诊断中。SADM是一种罕见的自身免疫性疾病，影响皮肤和肌肉。它被认为是皮肌炎（DM）的亚型，DM是一种全身性自身免疫疾病。SADM的确切原因尚不完全清楚，但据信涉及基因、环境和免疫因素之间复杂的相互作用。通常根据临床评估、血液检查、肌肉活检和皮肤活检来诊断SADM。SADM的治疗选择可能包括皮质类固醇、免疫抑制药物和其他支持措施以管理症状和预防病情进展。一位30岁女性出现间歇性烧灼感、疼痛性皮疹，主要出现在手部和面部。她的病史中有时在上半身（面部、颈部和胸部）出现多发性关节疼痛、慢性腰背痛和间断性疼痛性皮疹的六年病史。神经系统检查显示头皮压痛和上肢关节痛，肌力检查正常。皮肤检查显示两侧手臂和手部出现红斑疹。皮肤切片活检显示致密正鳞状角化、表皮萎缩、界面改变和胶状铁染色增加的真皮粘多糖，提示DM的可能。肌电图和神经传导学检查正常。左大腿MRI正常。C3和C4水平降低。包括MDA5在内的扩展肌特异性肌炎面板检查结果为阴性。对该患者采用甲氨蝶呤、羟氯喹和强的松等多种药物治疗方案。在一年的随访中，她的皮肤病变和急性发作有所减轻。临床医生在鉴别诊断具有反复出现的疼痛性皮肤病变的患者时应考虑纯皮炎性的无肌无力（ADM）。由于神经系统后遗症可能在病程中更晚出现，这种情况很容易被忽视。我们强调对这种特殊诊断的患者进行多学科管理。建议密切监测神经病变和相关后遗症的发展，包括恶性肿瘤。版权所有 © 2023年，Harazeen等。

We present a case of seronegative amyopathic dermatomyositis (SADM). This clinical entity should be considered in the differential diagnosis of patients with recurring, painful erythematous skin manifestations, and requires close monitoring for the development of neurological manifestations and malignancy. SADM is a rare autoimmune disease that affects the skin and muscles. It is considered a subtype of dermatomyositis (DM), which is a systemic autoimmune disease. The exact cause of SADM is not fully understood but is believed to involve a complex interplay between genetic, environmental, and immunological factors. The diagnosis of SADM is typically made based on clinical evaluation, blood tests, muscle biopsy, and skin biopsy. Treatment options for SADM may include corticosteroids, immunosuppressive drugs, and other supportive measures to manage symptoms and prevent disease progression. A 30-year-old female presented with symptoms of intermittent burning, painful rash primarily on the hands and face. Her medical history was remarkable for a six-year history of multifocal joint pain, chronic low back pain, and intermittent, painful recurring rash in the upper body (face, neck, and chest). Neurological examination revealed scalp tenderness and arthralgia in the upper extremities, with normal motor strength examination. Skin findings included described an erythematous rash on the arms and hands bilaterally. Skin punch biopsy showed compact orthokeratosis, atrophy of the epidermis, interface changes, and increased dermal mucin on the colloidal iron stain, which are suggestive of DM. Electromyography and nerve conduction study were normal. The MRI of the left thigh was normal. C3 and C4 levels were reduced. The extended muscle-specific myositis panel including MDA5 was negative. The patient was placed on a multidrug regimen, including methotrexate, hydroxychloroquine, and prednisone. Within one year of follow-up, she was found to have reductions in skin manifestation and flare-ups. Clinicians should consider amyopathic DM (ADM) in the differential diagnosis of patients with recurring, painful skin manifestations. This condition can be easily overlooked as the development of neurological sequelae may be present much later in the course. We highlight the need for a multi-disciplinary management approach for patients with this unique diagnosis. Close monitoring for the development of neurological manifestations and associated sequelae including malignancy is recommended.Copyright © 2023, Harazeen et al.