M79.1Myalgia

M79.1 is the ICD-10-CM diagnosis code for myalgia. It belongs to category M79 (other and unspecified soft tissue disorders, not elsewhere classified), block M70-M79 (other soft tissue disorders) and chapter 13 (diseases of the musculoskeletal system and connective tissue). It is a header code, so it can't be reported by itself; one of its 4 subcodes must be used instead.

Within M79 (other and unspecified soft tissue disorders, not elsewhere classified), M79.1 is specifically for myalgia. Related codes cover rheumatism, unspecified (M79.0), neuralgia and neuritis, unspecified (M79.2), panniculitis, unspecified (M79.3), hypertrophy of (infrapatellar) fat pad (M79.4), residual foreign body in soft tissue (M79.5), pain in limb, hand, foot, fingers and toes (M79.6), Fibromyalgia (M79.7), other specified soft tissue disorders (M79.8) and 2 more.

To report this condition, pick the subcode that matches the documentation: M79.10 (unspecified site), M79.11 (of mastication muscle), M79.12 (of auxiliary muscles, head and neck) and M79.18 (other site).

Don't report M79.1 together with the conditions in its Excludes1 note: fibromyalgia (M79.7) and myositis (M60.-).

It has been part of ICD-10-CM since the code set took effect on October 1, 2015, and changed in FY2019 (expanded into subcodes).

Before ICD-10, this condition was coded in ICD-9-CM as 729.1 (myalgia and myositis, unspecified).