Is it normal to randomly start itching and break out in rashes that typically go away the day after?

URTICARIA = HIVES. An 'itchy' rash that can resolve in a day is usually called urticaria (hives). The cause of hives may not be found in up to 50% of cases. Hives can be triggered by many things such as food allergies, medications. Viral infections can also cause hives. If hives last > 6 weeks then the cause is usually not allergic (chronic urticaria). The treatment is antihistamines: benadryl, (diphenhydramine) zyrtec, allegra..