Moles or nevi are normal skin growths that develop from birth onward, most commonly during adolescence and young adulthood. Normal moles are usually uniform in color, round or oval and symmetrical. Congenital moles are present at birth and can be larger and darker. Patients with large numbers of nevi (>100) or asymmetrical nevi need closer monitoring for the development of skin cancer. Moles that are larger than 6mm, itch or bleed, change colors or are multicolored or asymmetrical should be examined by a dermatologist.