How To Cure Red Bumps Like Hives On Stomach?

hi ,I will be 40 in a few weeks, I am a female, I have been over the past few months been experiencing little red bumps, almost like hives but on my belly; I work out a lot but have for over 20 years, my diet is the same, my detergent the same, I love taking baths but that too I have always done..not sure what it is.. but it comes and goes, and when it comes it itches like crazy and the bumps are close to one another?? hope you can throw some sort of idea.. or thoughts my way..