Q. A 38 year old man presents to your office with complaints of tremor in the hands over the past couple of weeks. He has had an on and off tremor for the past couple of decades, especially when he drinks caffeine. He denies any trouble with motor power or gait. He denies any tremor in the lower extremities or face. He has a history of anxiety and began taking a low-dose corticosteroid for severe seasonal allergies within the past few weeks. There is no family history of familial tremor. His vital signs are normal. Physical examination demonstrates a high frequency tremor of both hands that is exacerbated with coordination testing with finger to nose testing. It is present even when you distract him during the evaluation. His motor tone is normal. The tremor is symmetric. You sent him for a complete blood count complete metabolic profile, TSH, and vitamin B 12 level which are all normal. What is the most likely diagnosis?