My DS7 gets upset about getting water on his sleeves when he washes his hands. He's had some germ-aphobia that has come and gone and come back.
He did the involuntary throat clearing, eye tics for awhile--come and gone, come and gone again.
I myself has some occasional anxiety- I think it's hereditary, nurture, and for some kids part of being gifted. Sort of a soup or a perfect storm. Unfortunately, he saw me get a bit freaked out by germs, and it probably triggered his natural tendency. Honestly, though, I think something would have triggered it eventually.
My strategy is not to explain or force something in the moment. Anxiety is a powerful, involuntary emotion and will not respond to logic or any kind of coercion.
I wait until the moment is has passed, then ask in an open ended way, what is so frightening. Then address (not dismiss) the fears one at a time- in our case, I explained that yes, germs can make us sick. However, most germs are harmless and even the ones that make us sick are usually temporary. We also discussed a short list of "reasonable" strategies to keep the spread of germs to a minimum--once those things (hand washing at certain times, for instance) are done, we can forget about germs.
I think with kids (and anyone who suffers from anxiety), it's important to keep the conversation open and judgement-free. My husband made it pretty clear that he was displeased with some of DS's anxiety behaviors as a way to "snap him out of it." The result is that DS didn't get over the behaviors, he just tried to conceal them--all the while, the anxiety grew inside and poor buddy felt like he couldn't talk to anyone about his feelings.
