Can wash powder give an allergic reation of little rasised itchy bumps on my back arms folded clothes became extremily itchy.

Yes: You may be allergic to one of the ingredients. Another possibility is the anti-static strip if you do use it when drying your clothes. Try some hydrocortisone cream on the itchy areas . in the meanwhile, try another brand of laundry detergent . Once you are sure that you don't have a reaction to it (takes several days), then you will need to rewash everything touched by the old detergent.