Question: Our pediatrician just saw a patient who had a contusion on her left foot. However, the note did not indicate whether or not the bruise was caused by a trauma. How should I code this? North Carolina Subscriber Answer: While it is unusual for someone to bruise without an identifiable cause, it is certainly possible. Some medical conditions and medications can thin the blood to the point where an individual bruises easily, even to the point of bruising without a known trauma being the cause. If this is indeed the case, you should report R23.3 (Spontaneous ecchymoses). You can use this for bruises larger than 1 centimeter; you can also use this code for bruises less than 3 millimeters (called petechiae). Contusions less than 1 centimeter but larger than 3 millimeters are known as purpura and are coded to D69.-. If it is not the case, and your pediatrician does confirm that the contusion was caused by a trauma, then you would look to S90.32- (Contusion of left foot), using the placeholder X and seventh character A, D, or S to describe whether the encounter was initial, subsequent, or sequela. You should also follow this code with an external cause code from Chapter 20 to describe how the injury occurred. But this is one of those times when you will definitely need to connect with your pediatrician to determine the most specific code for the diagnosis.