RESUMEN
BACKGROUND: Statin-induced necrotizing autoimmune myopathy (NAM) has been recently characterized. Herein we report an accurate description of the clinical and histological characteristics of cutaneous rash associated with NAM. PATIENTS AND METHODS: A 61-year-old woman presented a skin rash involving the face, the chest and the back of the hands with heliotropic distribution coupled with proximal symmetrical muscle weakness. Rosuvastatin had been introduced 8 months earlier. Creatinine kinase levels were dramatically raised. Screening for lupus and dermatomyositis antibodies were negative. The cutaneous histology was consistent with neutrophilic lupus while a muscle biopsy revealed no inflammation but showed necrotic and regenerative myofibres. Finally, antibodies directed against 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGCR) were found at high levels (1658UA/ml vs. normal<13.0UA/ml), resulting in diagnosis of necrotizing autoimmune myopathy (NAM). Intensive immunosuppressive therapy resulted in excellent improvement. DISCUSSION: NAM is a severe acquired autoimmune myopathy characterised by severe proximal weakness and specific positive antibodies (anti-HMGCR or anti-signal recognition particle). It is classically associated with statin use. Some extra-muscular symptoms have been described in previous studies. We report the third accurate description of cutaneous rash associated with statin-induced NAM involving HMGCR antibodies. The skin rash was evocative of connective tissue disease and our diagnosis was based on immunology and muscle histology. CONCLUSION: Dermatologists must be able to recognise this rare entity of "pseudo-dermatomyositis" and then discontinue statin intake if present and carry out further investigations consisting of muscle biopsy and serological tests.
