Bullmastiffs are the perfect example of form follows function. They are bred from Mastiffs (60%) and original Bulldogs (40%) for the purpose of accompanying gamekeepers on their rounds in the vast English estates. That 60/40 combo baffles my math mind. Read more - blog post on the Gamekeeper's Dog.
Both Mastiffs and Bulldogs have a tendency toward having dry or crusty, even cracked noses. Wouldn't you know it, Bullmastiffs inherited that predisposition from both sides of the canine family. Many Bullmastiffs have a bit of a dry nose, some areas of crust, but if your Bullmastiff’s nose is covered with a harder crusty, almost scab-like tissue, like the noses below, Nasal Hyperkeratosis may be the culprit!