Lilac is another rare coat color, and American bulldogs with this coat type mostly have a pale appearance. One notable aspect of the lilac coat is that it is diluted twice, first by the chocolate of the [bb] gene and second by the blue or [dd] gene. Both the genes affect the black coat, with the chocolate gene changing it to brown and the blue gene giving it a grayish-blue coloration. The combination of blue and brown provides the coat with a purplish or lilac coloration. Besides the body, one can even see the lilac pattern on the American bulldog’s nose, eyeliner, and paw pad.