My horse used to headshake really badly, his previous owner was thinking of having him put down, he didn't want to, he just didn't know what to do with him. He was also very sensitive to touch and brush over his head and neck. I tried riding him in a nose net, he would still shake a lot, but it was hard to know if the nose net flapping up and down was annoying him and adding to the problem. The trouble was because he kept shaking, he made the net flap up and down.
There seem to be so many different causes for headshaking, but because my horse was so sensitive to brush, I was inclined to think that the cause for his problem was damaged hair glands. I found that this could be treated using electrolyte patches. I treated him for 20 days with the patches and the difference was amazing. He stopped shaking and also now loves having his head and neck brushed. Also his coat which used to be dull and stary is now beautiful so obviously by healing the hair glands to cure the headshaking, he has also benefited from an all over conditioning effect.
As he can now cope with schooling and training, I have just started competing him, but although previously a nose net didn't seem to help the problem at all, I do find that if I don't continue to use one he seems to have an itchy nose and wants to rub it, so I think that he also suffers with pollen allergies, which the electrolyte patches don't cure. This might be helpful to people to be aware that in some horses the problems/discomfort/distress is actually due to more than one cause.
I've attached a picture of him at his first show.