How can i reduce itching and swelling due to hives?

Antihistamine: The combination treatment, sedating and nonsedating antihistamines, e, g, Atarax (hydroxyzine) plus zyrtec, works well. Known trigger should be avoided as well.

Hives: Remove the causative stimulating agent, if known. Try topical Benadryl (diphenhydramine) or Hydrocortisone and strongly consider addind oral antihistamines into the mix. I tend to treat with higher doses than once daily since skin oftentimes requires higher doses, but start with one and ask your doctor about dosing options.