My tummy is more sensitive to dust since it started containing a small person. I also get heat rash really easily all over the top half of my bump which causes a couple of days of really itchy red bumps.

Whenever my red itchy bumps have shown up i have put e45 cream or extra shea butter (what i am using to hopefully keep away the dreaded stretch marks) on in the evenings and lifted my top up when i am alone to give my skin some air, for me that has cleared up the itchy bumps within a couple if days.

Of course if you notice they flare up when you eat a specific thing or are exposed to something specific try to avoid that thing as it is probably an allergy.
If you are worried talk to your ObGyn but you might find, like me, that it is pretty simple to clear up.