Another cause is daily shaving. Your skin can grow soft through daily shaving and with exfoliation from the badger brush, could cause your face to glow red/irritated. Experiment and try to hone down the cause of the rash.
I used to have this problem until I realized I have sensitive skin and I need to be more choosy about the products I use, and I needed to invest more into skincare. Now I shave nearly every day without significant irritation. I don't get the closest possible shaves, but it's close enough and relatively comfortable.