Why do I have hives, and what gets rid of them?!

Why do I have hives, and what gets rid of them?

I just started getting them around the scalp and face area about 5 years ago. mabe once a year. then got them once a week for 3 weeks bout three years ago.Then they stopped for a couple of years. I have no idea what I could be allergic to. I only know I'm alergic to (raw) shrimp. Butt I cant make any connections to foods, perfums, soaps or anything. I worked as a landscaper for the last couple years except this year, and only had them once.the only constant thing about them is they start in the evening and are gone when I wake up. The thing is, they have just about been regular for about a month now, almost every day. I had a really bad out break a couple of weeks ago. I had went camping and swimming in a spring all day.I noticed my scalp starting to itch when I was about to leave, it took an hour to get home, by the time I got home, I looked like I got attacked by african bee's

Hives are produced by histamine and other compounds released from cells called mast cells, which are a normal part of skin. Histamine causes fluid to leak from the local blood vessels leading to swelling in the skin.

Hives are very common. Although they can be annoying, they usually resolve on their own over a period of weeks, and are rarely medically serious. Some hives are caused by allergies to such things as foods and medications, but the large majority of cases are not allergic, and no specific cause for them is ever found. Although this is frustrating to patients, such common maneuvers as changing diet, soap, detergent, and makeup are usually not helpful in preventing hives and for the most part are not necessary. I have them, and the best treatment I have found is antihistimine. Take the max allowed by your doctor.