What Causes Blood Red Spots On Lower Arm?

a couple of weeks ago i noticed blood red spots on my lower arm close to my wrist. they went away in a few days. now i have blood red spots again but on both arms - the ones on my right arm are close to my wrist and the ones on my left arm are midway and closer to my elbow. The spots are like one larger spot with 4 to 5 smaller ones below them. Any thoughts???