Fortunately most burns are minor and require only first aid and a dressing. However burns that affect a large area of the body are much more serious, can be life-threatening, involve intensive-care treatment and possibly several operations. Even some small burns, if they are deep, are treated with an operation. Usually the seriousness of a burn injury is determined by:

How much of the body is burned ( the “body surface area” or “BSA”),
How deeply the skin has been burned and
The general health and age of the person who has been burned.