What are some causes of severe trembling hands?

Several causes: Trembling hands, also known as tremor, has many possible causes. These include neurological conditions such as essential tremor and parkinson disease, but also other causes such as sleep deprivation, excessive caffeine, and anxiety. Discuss your symptoms with a doctor; neurologists who are movement disorders specialists have the most expertise in tremor.

Many: There are many causes of tremulous hands. Very few causes actually have to do with the hands themselves. There are many types of tremors with different characteristics and frequencies. Normally they are neurologic in origin. I would recommend evaluation by an neurologist.