What Causes Severe Itchy Rashes On Scalp, Neck And Chest After Taking Allopurinol?

Question: My husband is 69 years old, and in good health. He is on Allopurinol 300mg. 1x day, Metformin 500mg.2x day, Lisinopril 20mg. 1x day, Simvastatin 40mg. 1x day, Pantoprazole 40mg. 1x day, Tamsulosin 0.4mg. 1x day. He has been having a terrible rash and itching since April, our Dr. put him on Medrall pack first without much results then they gave him a cream that did nothing. From there she put him on prednisone which helped but as soon as he was done it started again only much worse. To start it was mostly his scalp, neck and chest. The longer it went on, the more things we tried, the worse it got. She put him on the prednisone again which gave relief but again as soon as he went off it revived up again. She sent him to a dermatologist who just said it was a rash and put him on the prednisone again for a much longer time. It still worked but not quite as good as before. So now its the middle of August and he is still in agony not any closer to know what the problem is, and no one has even offered to do blood work or any testing of any kind. As you can imagine this is very frustrating. We have tried to eliminate everything we can possibly think of from soaps to sheets to pills to food and we have nothing. The only thing we think it might be is the Tamsulosin but he has been off of that for about 2-3 weeks and it still persists. Also as the rash has developed it now travels all over his body from the top of his head to the bottom of his feet. The Tri-Calm didn't even touch it. Nothing works or even helps a little bit. Is there anything you could suggest that might give my husband some relief, PLEASE. I thank you for your time in this matter. Our e-mail is YYYY@YYYY . My name is XXXX and my husbands name is XXXXXXX thank you, again.