Question: A 7-year-old girl was playing yesterday with her next-door neighbor, and they were running around after each other with squirt guns. The neighbor’s little dog must have felt the 7-year-old was threatening the other girl, and the dog bit her on the leg. On examination, she has multiple jagged bites and a painful open wound in the right lower leg. Assign the external cause code for the dog bite.

Answer: W54.0XXA, Bitten by dog, initial encounter.

We are not being asked to assign for the open bite here. Instead, we need to assign the external cause code, which is a secondary code that can be found in Chapter 20, External causes of morbidity. This code explains the cause of the injury.

Looking in the ICD-10-CM External Cause of Injuries Index, see Bite, dog W54.0. Verified in the Tabular, W54.0 refers to Bitten by dog. However, this code is unreportable, because it requires a 7th character. W54.0XXA should be assigned to show it is an initial encounter and patient is receiving active treatment.

See the next coding exercise here.