Yes, Please. My Husband Had Rotator Cuff Surgery Last Week

Yes, please. My husband had rotator cuff surgery last week and has been on hydromorphone for pain. He took quite a bit the first few days but very few the last couple. His last dose was last night (1 pill). This afternoon his good hand started itching and is now red and a bit swollen. He's begun itching on his leg, as well. Could this be the hydromorphone?
Thank you for your time.