Necrotising autoimmune myopathy (NAM) is caused by immune system deregulation. The inflammatory component is generally very low key, contrarily to the other types of autoimmune myositis. It is, to a large extent, associated with the presence of autoantibodies directed against SRP and/or HMG-CoA Reductase (HMGCR) proteins.
An observation from Brazil relates the combination of NAM with erythema-type skin signs in a young female 8-year-old patient:
- the muscle biopsy showed an appearance of necrosis and an increase in HLA class I labelling;
- the skin biopsy showed perivascular inflammatory lesions;
- the anti-SRP and anti-HMGCR antibodies were negative, whereas CPK levels were very high.
