I woke up with hives 2 mornings in a row. on day 3, in the middle of the day, i have itchy red bumps on my elbows & knees. what could this be?

Sorry: You should see your dermatologist for treatment and evaluation. There are many diseases that could cause this.

Hives: Hives come and go. The best therapy is to decrease the itch-scratch cycle by taking higher doses of non-sedating antihistamines during the daylight hours and the sedating antihistamines at nighttime to get some sleep. See you allergist if this persists.