Problem With Pruritus Of Both Forearms. Prescribed With Steroid Creams And Nothing Helped. Any Ideas?

Question : I have a problem with puritis of both forearms. I have had reoccurrence of this off and on for 5-y yrs. I start itching and when I scratch it forms small bumps. No drainage or anything from these except when I scratch the skin off. I have been seen by PA from dermatology and have been prescribed all types of steroid creams, and none have helped. Also prednisone by mouth helped at first onset, but when reoccurred did not help. I am now seeing a Dermatologist and he has done punch biopsy, shave biopsy, and skin scrapings. None have shown anything except excoriations r/t scratching. He put me on dapsone but I cannot say this has helped. Neither do antihistamines. The best relief I've found is with the use of topical menthol, higher % and ice packs. Any ideas? I also have seen an allergist who did skin test and never really found anything to cause this.