Gluten intolerance manifests with damage to the villi in the small intestine. The tips of the villi produce lactase. Exposure to gluten proteins from wheat/barley/rye can damage the villi and their ability to make lactase.
There are other reasons to end up lactose intolerant. Some of it can be traced to genetic and racial heritage. Lactase production can drop as individuals age. It can happen even if you aren't gluten intolerant. I counted myself in this category for years and just avoided foods containing fresh milk. Coffee with heavy cream has no lactose and never upset my stomach.
My parents spent lots of money carting me to ear, nose and throat doctors. My sinuses were always a disaster. I was subjected to a tonsillectomy in hopes that removing the tonsils would remove a reservoir of infection. That did nothing. Perpetually living on antihistamines wasn't really helping either. Discovering the wheat connection was a total accident. I removed wheat and diary from my diet about 10 years ago. My sinuses were clear for the first time in my life. About 18 months into this happy state, I came home to find the house fragrant with a freshly baked pizza. I ate one piece and triggered the running nose, throat clearing and three ring circus in my gut.
I suggest reading through "The Gluten Connection". You would be surprised how many different ways a gluten intolerance can be manifested in humans.
