A blue nose pit bull is a pit bull whose nose and fur may range in color, from light gray to deep charcoal. This gray coloring is widely referred to as blue.
The "blue" coloring in these pit bulls is caused by a recessed color gene. This gene causes reduced melanin levels in dogs that would normally have black coloring, resulting in a dilution of color in their fur, and possibly their nose, which appears as gray. Due to their recessive coloring, blue nose pit bulls may be more prone to skin disorders and certain health issues than regular pit bulls.