Stress can be a very important means for us in certain situations (fight or flight situations) but stress can also have very adverse effects on the body. These can manifest as many different things depending on how your body deals with stress. GI complains such as diarrhea
or constipation, headaches, increased heart rates and perspiration are common symptoms related to stress, but hives
are not as common a presentation of stress. For this reason, it is important that you be evaluated by your primary care doctor
who will be best able to evaluate your medical history and presenting symptoms and decide upon the appropriate work up. This may include lab studies and imaging studies. They may also recommend a referral to a specialist. Some of the other options that they may consider are allergic reactions, although this seems less likely in the setting of hives that appear with stress only. They may also recommend medications to help with you deal with the stress depending on what they find. The most important first step is to be evaluated by your primary care doctor as it is difficult to diagnose this based upon the information given here.