Random Breakouts?

For about a year now, I have been getting random breakouts on my stomach/back/chest area. It acts like hives, because it completely covers the skin area.. However, on the front of my body- it looks like tiny zits. They have whiteheads and will pop. The breakout on the back of my body looks more like welts, though. They are swollen and red, without whiteheads. It happens randomly, and comes and go's without treatment. I don't know if I might be allergic to something, but it's starting to scare me. I initially thought I was allergic to chlorine, because it ALWAYS happens after a day at the pool. But it also happens on days that I don't go to the pool, so I can't figure out what's causing it, any ideas?

[Dr Santos]

Hi,
How are you? The cause of hives is usually not known and it is important that the trigger can be identified. A journal may help identify the possible cause in order to avoid them in the future. Aside from allergy, it could also be due to irritation, or skin conditions such as sweat dermatitis. Keep the area dry and drink plenty of fluids. Over-the-counter antihistamine medications may also help.If it persists, you may need to have this checked by your doctor for proper evaluation. Direct clinical examination is important.Take care and regards.