eduardoan,
If the bumps are small and are actually in the veins near the surface of the skin, they are called phlebolithes. These are tiny isolated blood clots in the superficial veins. They feel like tiny stones under the skin, they are hard. These are in no danger of breaking loose, like their cousins the deep vein thrombosis (DVT).
Leukemia is actually a disorder of the blood, where there are too many white blood cells. The blood also has a low number of platelets, which are required for proper blood clotting, so leukemia patients will often have problems with easy bruising and bleeding. But, the usual presenting symptoms of leukemia are that of just feeling bad or sick. The patients usually feel weak, have fevers, malaise, nausea. Then, on a routine blood test, the CBC, the leukemia is picked up.
Psoriatic arthritis affects the joints and spine in a particular pattern. It may also have the associated skin rash, but not always. Nodules, though common in rheumatoid arthritis, are usually not part of psoriatic arthritis.
She should probably have her physician take a look the bumps, to see what they are exactly.
Good luck.