Moles are common lesions we all develop on our skin over time. They are made of pigment cells called melanocytes. These can form during childhood and adolescence as well as through adult life. Moles can be flat and can, as part of their life cycle, become more raised in appearance over time. Seek advice for any moles with unusual features: asymmetry where one half of the mole appears different to the other half; a border or outline that looks irregular; uneven colouration where the mole does not appear uniform in colour or appears very dark; a mole being larger than others, typically more than 6 millimetres in size; evolving changes in size, shape, colour or feel; or any itching, bleeding or crusting.