What is the medical term meaning hives?

Hay fever is an occurance that occurs year round when we become allergic to certain things that aren't always blooming, its natural to get sick around the spring and autum because that's the time hay fever comes in. However hay fever can mostly relate to the substances that effect your environment, they might also be food or drink, no that's just something your always allergic to just blame it on the hay fever next time you can't breath properly, can't smell and can't think that's what hey fever is