Coding Tip: Cellulitis and DM Coding

Is Cellulitis always a skin complication of Diabetes Mellitus?

In the Alphabetic Index of ICD-10-CM, when indexing diabetes there is an entry under “with” for skin complications NEC. This has brought up many question over the past year regarding coding of cellulitis in patients that also have a diagnosis of diabetes. Are these two linked by the definition of “with” in ICD-10-CM?

Finally, there is official guidance on this subject.

NO, the link is not assumed when patients have cellulitis and diabetes documented. The physician would need to document the cellulitis as a diabetic skin complication or link the two conditions with verbiage such as “due to”, “associated with” or similar terms. If the documentation is not clear and the coder is unable to determine whether a condition is a diabetic compilation and/or the ICD-10-CM classification does not provide instruction, it would be appropriate to query the physician for clarification.

Even though there is an entry under “with” for skin complication right after the main term of diabetes, there is not an entry for cellulitis. Per the 4Q2017 AHA Coding Clinic, the “with” guideline does not apply to NEC (not elsewhere classified) conditions. Only specific conditions would be linked by these terms. If this were the case, then any skin issue would be considered as a diabetic complication when patients have both a skin condition documented and diabetes. An obvious example of this would be a patient with diabetes and also acne. Most likely the acne is not a complication of the diabetes but of puberty or other skin disorder.

Here’s the definition of “with” from the ICD-10-CM Official Guidelines for Coding and Reporting FY 2018, Pages 12-13:

“With”
The word “with” or “in” should be interpreted to mean “associated with” or “due to” when it appears in a code title, the Alphabetic Index, or an instructional note in the Tabular List. The classification presumes a causal relationship between the two conditions linked by these terms in the Alphabetic Index or Tabular List. These conditions should be coded as related even in the absence of provider documentation explicitly linking them, unless the documentation clearly states the conditions are unrelated or when another guideline exists that specifically requires a documented linkage between two conditions (e.g., sepsis guideline for “acute organ dysfunction that is not clearly associated with the sepsis”). ICD-10-CM Official Guidelines for Coding and Reporting FY 2018 Page 13 of 117

For conditions not specifically linked by these relational terms in the classification or when a guideline requires that a linkage between two conditions be explicitly documented, provider documentation must link the conditions in order to code them as related.

The word “with” in the Alphabetic Index is sequenced immediately following the main term, not in alphabetical order.

Here are some examples of coding cellulitis in patients that also have documented diabetes:

• Patient presents with cellulitis of the right foot and toes. The patient also has a history of type 2 diabetes and is currently using insulin now for the past few years. There is no further link made by the physician of the cellulitis being a complication of or related to the diagnosis of diabetes. In this case, the coder would not code as a skin complication of diabetes. Before the link can be made, the physician would need to be queried for clarification of the link of the two diagnoses.
• Patient presents with cellulitis of the right foot and toes and has documented diabetic foot ulcer at the site and related cellulitis. In this case, the causal link has been made and it would be appropriate to report as a skin complication of diabetes.
• Patient presented with type 1 diabetes having issues with dehydration. They were admitted for observation status due to the fear of the patient developing DKA for IV fluids. During the observation stay, it is noted that the patient has a few areas of severe acne and a dermatology referral was made to help with treatment of this condition. In this case, the coder would not code as a skin complication of diabetes. This is typically not a skin complication associated with diabetes so the coder should not query the physician.

References:
AHA Coding Clinic® for ICD-10-CM and ICD-10-PCS, Fourth Quarter 2017 Page: 100-101
ICD-10-CM Official Guidelines for Coding and Reporting FY 2018 Page: 12-13

Happy Coding!

The information contained in this coding advice is valid at the time of posting. Viewers are encouraged to research subsequent official guidance in the areas associated with the topic as they can change rapidly.