I think Dex's suggestion of ph change might be spot on, however - I'm a real silver bug and Nivea have a roll-on 'Silver' which contains nano particles of silver (and no aluminium).
Silver is a very effective antibacterial and bacteria are the cause of the u/a problem.
I've used the Nivea one for years - no problems at all. Mind you, I don't think I've ever had blocked glands.
