Moles are a common skin condition that affects many people. They can appear anywhere on the body but most commonly occur on the face and neck. Moles can range in colour from pink to light brown, dark brown or even black. Moles typically appear during childhood and adolescence, although most people have 10 to 40 moles, some of which may alter in appearance or fade with time. They are usually round or oval but can be very small or large, flat or raised, smooth or bumpy, and may or may not have hair growing out of them. What Causes Skin Moles? Moles are formed when melanocytes in the skin’s cells (melanocytes) grow in clusters or clumps. Melanin, the natural pigment that gives your skin its colour, is produced by melanocytes distributed throughout your skin.