1. ICD-10-CM Codes
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2. M00-M99 Diseases of the musculoskeletal system and connective tissue
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3. M30-M36 Systemic connective tissue disorders
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4. M33- Dermatopolymyositis
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2020 ICD-10-CM Diagnosis Code M33.9

Dermatopolymyositis, unspecified

2016 2017 2018 2019 2020 Non-Billable/Non-Specific Code

• M33.9 should not be used for reimbursement purposes as there are multiple codes below it that contain a greater level of detail.
• The 2020 edition of ICD-10-CM M33.9 became effective on October 1, 2019.
• This is the American ICD-10-CM version of M33.9 - other international versions of ICD-10 M33.9 may differ.

• A subacute or chronic inflammatory disease of muscle and skin, marked by proximal muscle weakness and a characteristic skin rash. The illness occurs with approximately equal frequency in children and adults. The skin lesions usually take the form of a purplish rash (or less often an exfoliative dermatitis) involving the nose, cheeks, forehead, upper trunk, and arms. The disease is associated with a complement mediated intramuscular microangiopathy, leading to loss of capillaries, muscle ischemia, muscle-fiber necrosis, and perifascicular atrophy. The childhood form of this disease tends to evolve into a systemic vasculitis. Dermatomyositis may occur in association with malignant neoplasms. (from Adams et al., Principles of Neurology, 6th ed, pp1405-6)
• An inflammatory muscle disease accompanied by muscle weakness and skin rash
• Progressive condition characterized by symmetric proximal muscular weakness with elevated serum levels of muscle enzymes and a skin rash, typically a purplish-red erythema on the face, and edema of the eyelids and periorbital tissue; affected muscle tissue shows degeneration of fibers with a chronic inflammatory reaction; occurs in children and adults, and in the latter may be associated with visceral cancer or other disorders of connective tissue.

• 2016 (effective 10/1/2015): New code (first year of non-draft ICD-10-CM)
• 2017 (effective 10/1/2016): No change
• 2018 (effective 10/1/2017): No change
• 2019 (effective 10/1/2018): No change
• 2020 (effective 10/1/2019): No change

Reimbursement claims with a date of service on or after October 1, 2015 require the use of ICD-10-CM codes.