What would be causing Hives?

What is causing these hives/trouble breathing?

• Ok so Friday morning I awoke with many hives(nettle rashes) all of my torso. They were HUGE not little red dots but maybe 1inch by 1inch and after a while they connected to make bigger ones. I took medicine and it went away the next hour. After I came home from work and went to my room, I went again developed hives within 30 minutes. I then had difficulty swallowing and had to take large breaths to get air & my voice became raspy. THe hives came back worse then earlier that day & there were more in different places. I took medicine and went to sleep. I awake with hives on my body & on my face. My lips were swollen and it was hard to swallowing/breath. I went to the doctor and he gave me medicine. Now It is time to find out what is causing this. Last week I got a new bed, and 2 weeks ago I adopted two guinea pigs. Help? the doctor is saying this allergy is causing Anaphylactic shock& that is it serious. If it is my guinea pigs, should I test other bedding/hay or get rid of them right away?

• Answer:

  This is an anaphylactic reaction which means you need to keep an EPI pen on hand at all times! Your doctor should refer you to an allergy specialist to help figure out what exactly you are allergic to. Symptoms such as hives and difficulty breathing are not to be ignored because they can become worse next time. Please see a medical professional immediately!