I sympathize with you because I went through similar issues, albeit not for 10 years. I have seasonal allergies, in particular pollens, dust mites and cats against which I have been getting shots every months for over 15 years which keeps it under control. However, after I got Covid in Sept 2022, I developed a recurring sinus infection that also significantly affected my hearing (I have worn hearing aids for 18 years). Getting antibiotics every 6-8 weeks became routine. Sleeping was interrupted every few hours. Immunologist, ENT and Primary Care Physician indicated it was Long Covid. Gradually, I started having annoying skin rashes, and I got from the Dermatologist about 8 different prescription creams and ointments - it was a trial and error game, sometimes there was relief for a week or two, and it would come back. In March of 2025, I got Covid for the second time. The sinus infections intensified and my hearing deteriorated further to severe. Since conventional medicine apparently was not helping, I went to see a DO who suggested I try Nicotine Patches (I am not a smoker!), starting with 14 mg patches for several weeks, than continuing with 7 mg patches. Reluctantly, I started using patches daily. After about 3 weeks, I noticed that the skin irritations and rashes were rapidly vanishing. So did the sinus infections. They are all gone. The hearing loss cannot be reversed, reason why I am going through a series of tests to get a cochlear implant (I posted about it in the ENT discussions).
I am continuing with the 7 mg patches. I had no side effects like dizziness, restlessness etc. others had experienced and gave up. I only have minor temporary redness of the skin where a patch was placed, but nothing that bothers me. I make sure I don't place a patch were there is still some redness. Regarding nicotine patches in general, I found a few research studies were done in Europe and in Korea, some using lab animals, others with relatively small groups of participants that showed an improvement of the immunity system.