The common wart is due to a viral infection of the skin by the Human Papilloma Virus (HPV).
They are mostly quite easy to diagnose, but this can be confirmed if you see little black dots in the wart if it is pared back.
Many treatments are available but can be time consuming, disappointing or difficult, for example, ‘freezing’ them with liquid nitrogen, or applying wart paste (salicylic acid) and paring them back.
Sometimes in kids they can be ‘bought’ off or respond to hypnosis [1] – excellent if there are many.