Amyopathic dermatomyositis (ADM) is a specific subtype of dermatomyositis (DM), which refers to skin lesions typical of dermatomyositis without the objective signs of myositis, and laboratory tests such as serum enzymes, electromyography, and muscle biopsy are unremarkable or only slightly abnormal. The first appearance of dermatomyositis without myositis was named “DM siné myositis” by Jim Gilliam, and in 1975 Krain1 first published a paper on 6 patients with initial onset of typical dermatomyositis lesions without myositis, but all of these patients subsequently developed myopathy. Pearson2 first introduced the concept of “dermatomyositis without myopathy”, and this designation became widely accepted after the efforts of Euwer and Sonthimer. In 1993, Euwer and Sontheimer4 proposed the following diagnostic criteria: 1) skin lesions characteristic of DM (initial Gottron’s rash, perineural erythema, dilated capillaries, and periorbital purplish-red puffy patches); 2) skin pathology consistent with DM; 3) no clinical evidence of proximal muscle weakness within 2 years after the appearance of skin lesions; 4) skin lesions 4. normal muscle enzyme levels (creatine kinase, aldolase) within 2 years after the appearance of the skin lesion. Exclusion criteria included: 1. History of high-dose systemic immunosuppressive therapy for more than 2 consecutive months within 6 months after the appearance of skin lesions. (The initial stage is the start of systemic immunosuppressive therapy, muscle lesions may not be obvious, it is difficult to exclude DM); 2, the occurrence of skin lesions with a history of drug use that can cause DM-like skin lesions, such as hydroxyurea, statins9 and so on. In 1999, Sontheimer5,6 advanced the time limit to 6 months and divided the disease into confirmed ADM and provisional ADM (meaning that the disease duration was between 6 months and 2 years) according to whether the absence of myopathy reached 2 years. There are also some patients with dermatomyositis-like skin changes but only subclinical mild myogenic damage (including serum muscle enzyme profile, electromyography, and muscle biopsy), which are called micromyopathic dermatomyositis or hypermyopathic dermatomyositis, and Sontheimer refers to them and ADM together as clinically amyopathic Sontheimer refers to it and ADM together as clinically amyopathic dermatomyositis (CADM). Since most of the current literature understands the concept of CADM as ADM. In the following, we still use ADM to describe some of the CADM. In 2006, Cao Hua8 pointed out that the diagnosis of “clinically amyopathic dermatomyositis” is biased, so that it is more emphasized as dermatomyositis, and the name “dermatomyositis-like dermatitis” is more accurate. The name “dermatomyositis-like dermatitis” is more accurate and refers to the typical skin changes of dermatomyositis with a clinical lack of myositis manifestations within 6 months to 2 years of onset. However, there is no consensus on this nomenclature.