Play therapy is geared toward young children (as young as 2) and uses a variety of activities, such as painting, puppets and dioramas (a re-creation of a natural setting which shows a specific moment in time) to establish communication with the therapist and resolve problems. Play allows the child to express emotions and problems that would be too difficult to discuss with another person.
An example of a play therapist referral might be a 5-year old who is having trouble separating from mom and attending kindergarten. There are many more examples of more intense needs such as sexual or parental abuse.