I Have Little Red Itchy Bumps All Over My Arms, What Do You Think It Is?

Could be a number of reasons.

Did you change your detergent? Have you used a different soap? Have you used different lotions? Have you eaten any odd foods? Have you washed your bedding recently? Do you wear clothes that haven't been washed consistently; such as work clothes around possible mechanical oils? Do you have clogged pores causing arm like skin ache due to hormones?

If they go away after two days it could be just an allergy. If the symptoms continue, you may look into randomly eliminating possible effects until you find a solution.

I find using a 'olive & aloe' organic moisturizer (unscented-paraben free) for sensitive skin found at health stores works really well; and also re-cleaning the bedroom fabrics (ei: Carpet, bedding, mattress) or sofas where possible pet-dander or fluids could have tainted hygienic sanitary cleanliness.

Good luck, and happy scratching!

Could possibly be heat rash. Some people's skin erupts in little bumps when they are hot. However, heat rash doesn't really last longer than two days. If it isn't heat rash, I would recommend washing your bedsheets

I've had that before and I think that is was a minor allergic reaction to a tree that I was in, or maby it was a insect in the bark.
Well it should go away eventually, but I had a shower and washed my arm and it seamed to co away soon after that. If it dosn't stop itching then you should put some anti-itch gel/cream on it.

If it dosn't go away in a day or you start to feel ill, go to your General doctor in town.