Rhododendrons: Rhododendron has a silver leaf?

I noticed that one of my rhodies has a siver leaf that actually looks like shimmery paint. Is this some kind of a fungus? What would cause this and how do I get rid of it? It is only on one or two leaves. Thanks for your help.

 

Thankfully we haven't found it on ours. Found you this, lily. Hope it helps See....

http://www.rhs.org.uk/advice/profiles0703/silver_leaf.asp

 

Thank you for the link Luddite. I haven't seen any brown staining on the wood. I just picked off the 2 leaves that were showing silver. I'll keep an eye on it. I wonder if it will spread to my other rhodies. If it does, I'd rather just pull it up and get rid of it altogether.