Well I've not talked about a scientific association between hair whitening and sinusitis. I have opined my question according to the observed phenomenon. You may find people around who have both symptoms simultaneously.
There is no association with allergies and hair whitening. Your cells determine when you will start to lose the color in your hair. And it is based on heredity so if your parents' hair went gray or white at an early age then you may also. The only other thing I have heard about hair color is when a person has chemotherapy for cancer and they lose their hair that it came back a different color and texture.
There might not be an association scientifically proved as yet between sinusitis and hair whitening, but it is general observation that the two occur simultaneously in most of the cases. 95% people having sinusitis I have met also had hair whitening.