Sinus infections and Celiac Disease/Gluten Intolerance sometimes go hand in hand. When one is diagnosed with this disease/intolerance, gluten needs to be removed from the diet because the body sees gluten as a foreign object or a virus and the immune system starts to attack. When the body's immune system is always in attack mode it is weak and unable to fight off infections or bacteria. The bacteria builds in your system and the immune system goes into overdrive and cannot fight it off. Think of it like when a person has worked a lot of hours, comes home cooks, cleans, puts kids to bed, goes to bed late and does not get enough sleep. What winds up happening is the person is exhausted and does not perform 100%.
A sinus infection that is treated with antibiotics will only kill about 99% of the bacteria and 1% is still left in the body. When the immune system is weak it cannot kill the rest of this and every time another infection starts the bacteria percentage is increasing.
The best way to stop these repeat sinus infections is to stop eating gluten, dairy and anything the body shows an allergic reaction to.
Remember though Celiac is an autoimmune disease and when gluten is ingested the body sees it as a virus or foreign matter and tries to attack it. It is not attacking gluten it is attacking other organs, tissues, muscles and bones in the body and weakening your immune system.