I am sensitive to flannel. I have to wash it really well and dry it in the dryer, not on the clothesline. I get laryngitis and lose my voice when working with it if it's not washed well.
Also, I can only stay in the fabric store about 15 minutes before I begin sneezing. I have to wash everything before I cut it. Gets a little troublesome. Have to keep my sewing room aired out or I will sneeze in there too.