I've Developed A "rash" Of Small Raised Pumps - It

I've developed a "rash" of small raised pumps - it began as simple itching around the navel w/o the pumps - then the itching spread to both the upper & lower abdomen with the pumps appearing w/I 2 days - there is no redness - I've been using a steroid cream as the recommendation of my pcp but there is no improvement and it has spread to my upper thighs and beneath my upper arms - the itching is reduced by the cream but does not go away entirely and is severe enough that it is interfering with my sleep