 [ Symptoms ] thumb is discolored and swelled very painful to touch or put in warm water it turns black when i put it in warm water started about three weeks ago with swelling and discoloring it looks like a bruise on the bottom side up toward the outside tip and is swelled from the bottom crease at the joint up to the tip i have sever pain when i press it against something or try to use it sever pain when in warm water and turns black it does not hurt to bend it and i did not sprain or smash it it is always cold from the knuckle to the tip and feels numb most of the time until i try to use it or push on it thank you [ Disease ] i had the same problem with my thumb and 2 fingers next to it it was caused by a blood clot they dissolved the clot and the two fingers cleared up rapidly but the thumb has not cleared up yet i will have to go back to be checked for another clot or possibly gangerine