I'm 21 years old. Ever since I was little I have had very mild food allergies which usually result in hives that last a couple hours at the most. I haven't had an allergic reaction in about 8 years though. Four days ago I had a hives outbreak and they've been coming and going but I can't get them to go away completely. I'm pretty sure I stopped eating what is making me allergic but I'm still getting really itchy breakouts, especially at night when I'm trying to go to sleep. How long do hives last? Should I start taking medication?
Yes, taking an antihistamine is very reasonable if you have hives. There is over the counter benedryl, and now loratidine and zyrtec, all of which can help.
I'm concerned that you have tolerated hives related to known food allergies without further evaluation. Hives are a significant symptom, and can be a warning sign of a far more life threatening allergic reaction, anaphylaxis, which can happen suddenly and unpredictably. It is important for you to know what is making you react, and avoid it. There are some tests that can be done by allergy specialists to determine your allergies with specificity.
Of course, it is possible this isn't hives at all, but some other cause of an itchy rash, worse especially at night--scabies comes to mind!
Don't hesitate to make an appointment if you'd like us to help sort it out.