A wart is generally a small, rough, typically on hands and feet but often other locations, that can resemble a cauliflower or a solid blister. They are caused by a viral infection, specifically by human papillomavirus 2 and 7. There are as many as 10 varieties of warts with the most common being considered largely harmless. It is possible to get warts from others; they are contagious. They typically disappear after a few months but can last for years and can recur.