Yes but you run a risk of making the keloid worse. A keloid is an exaggerated response to healing via scarring and getting a tattoo can possibly make it worse because the tattoo process causes damage to the underlying dermis in the skin. There are no guarantees what the results are but a history of keloids is not promising.
Keloid skin can be tattooed, but the ink might turn out differently, as keloid skin have a different shade compared to your outer skin. Also some kiloids are raised, so one has to be cautious with tattooing the area.
I would not recommend it. Keloids can stay the same size for a while, but they could also grow. Unless you are going to get the keloid removed, you might want to find another part of your body to tattoo.
