[Extensive digital necrosis during dermatomyositis associated with MDA-5 antibodies].

BACKGROUND: Dermatomyositis (DM) is an inflammatory disease associated with auto-antibodies in 50 to 70% of cases. A new antibody, anti MDA-5, has been described in association with a specific type of DM involving severe interstitial lung disease and minimal muscle disease. We report the first case of DM with MDA-5 antibodies and with interstitial lung disease and rapidly extensive digital necrosis.

PATIENTS AND METHODS: A 28-year-old male was hospitalized for asthenia, myalgia and subacute dyspnea. Examination demonstrated skin lesions with edema on every digit associated with purpuric and cyanotic lesions, as well as erythematous papules on the helix and the elbows, and Gottron's papules. Systemic corticosteroid therapy was initiated. The immunoprecipitation results indicated the presence of anti-MDA-5 antibodies. Despite corticosteroid therapy, the patient's respiratory status gradually deteriorated towards pulmonary fibrosis and rapidly extensive necrosis appeared on all fingers and toes. Theses effects were resistant to cyclophosphamide and immunoglobulin but were stabilized by cyclosporine.

DISCUSSION: Anti-MDA-5 antibodies are specific to DM and constitute a risk factor for severe interstitial lung disease (70% of cases) with a higher risk of mortality (40%). The cutaneous presentation of this DM is specific with palmar papules and mucocutaneous ulceration. Rapidly extensive digital necrosis has not been previously reported. No treatment has demonstrated superiority.

CONCLUSION: We report the first case of DM with anti-MDA-5 antibodies involving interstitial lung disease and massive digital necrosis. Because of the pulmonary risk, in the presence of clinical lesions containing anti-MDA-5 DM, screening for these antibodies should be carried out.