Cauliflower ear occurs most frequently in people who participate in close-contact sports, such as wrestling or boxing. In wrestling, for instance, trauma can result from opponents' heads rubbing or hitting one another during matches or from contact with the wrestling mat. Cauliflower ear is also common among rugby players and people who practice martial arts. People who participate in these activities are at higher risk than others. Protective head gear has long been commonplace in these sports, but these injuries can also occur in non-athletes as the result of accidents or physical altercations. They also can be a complication of infected "high" piercings in the upper area of the ear, through the cartilage.