What can cause easy bruising on my fingertips and palms of my hands?

I am a 42 year old female and, just recently, started bruising very easily, especially on my hands. A simple act of opening a car door caused an instant bruise on the inside of my ring finger. The vein puffed up painfully and just went black instantly. The other day when I was doing the dishes, my fingertips did the same exact thing. The only medication I am on, on a daily basis, is Synthroid, 100 mcg’s daily. I do not take pain meds or pain relievers, such as Motrin or Tylenol, or any other drugs for that matter. I only drink alcohol occasionally. Are there any doctors on this site that can help answer my question? Or has anyone gone through something similar?