Fever of Unknown Origin and Hepatitis as the Initial Presentation of Anti-MDA-5 Positive Dermatomyositis: A Case Report.

Petersdorf and Beeson first defined fever of unknown origin (FUO) in 1961, and subsequently, over the next 60 years, the definition of FUO has changed considerably. In the western world, non-infectious inflammatory diseases are the most common cause of FUO; however, in developing countries, infections remain the leading cause of FUO. Dermatomyositis (DM) is an autoimmune inflammatory disease of unknown aetiology which mainly affects skin and muscles. Anti-melanoma differentiation-associated protein 5 (MDA-5) positive DM generally presents with classical cutaneous manifestations, early interstitial lung disease, and patients generally do not have clinical features of muscle involvement. We present a case of a 39-year-old male who presented with FUO and hepatitis and was diagnosed as clinically amyopathic DM after two weeks of admission. Subsequently, he was found to have a high titre of Anti-MDA-5 antibody. This is the first case of Anti-MDA-5 positive DM presenting as FUO and hepatitis with a favourable outcome to the best of our knowledge.