I just want to share this. For years, I've been trying to determine the cause of chronic hives specific to my face, chin and neck. Food elimination diets, allergy shots, product elimination, antihistamines, etc. A few months ago, I finally stumbled upon my cure. I stopped using my electric toothbrush - and have not had hives (at least to the level of severity I was having them) since. I'm convinced.
If you have hives, explore this topic. If this post helps one person, I'd be happy. Google Vibratory Urticaria:
Those who are suffering from vibratory urticaria avoid lawn mowers, electric toothbrushes, jogging, playing drums, bumpy bus rides, jackhammering, etc. because they have an allergy to vibration. Vibratory urticaria tends to run in families and is caused by a rare genetic mutation that results in an exaggerated cell response to vibrating touch. It may also be an acquired response to a prolonged exposure to vibration. The afflicted report mild to severe allergic symptoms such as welts, fatigue, headaches, and blurry vision. Episodes can occur several times a day.
Here's a link but there are many others oout there. Good luck.