Hives at night?

Okay, in all my research on hives I still cannot find any information about this. When I wake up in the morning, I have hives obviously, I take a shower and the hives start going away rather quickly and they normally do not bother me during the day. Then every night around 8-9pm I start getting the hives again even though I was taking my meds all day. Is the something that they body does at night, like release toxins or something? I know other have experience this same pattern of sorts and I was just wondering if it would help explain some things. Reply if you can help.

-Anna Tweet