Primary Care Coding Alert

Understand contact type and synonyms for success.

When it comes to coding dermatitis, there’s plenty of confusion to go around. The profusion of synonyms, and the interchangeability of the key terms “dermatitis” and “eczema,” can make pinpointing the exact diagnosis codes next to impossible.

But if you remember these three important things the next time you comb through your provider’s notes, you’ll be able to find just the right ICD-10 code to describe a patient’s condition.

1. Know the Difference Between Irritant- and Allergic-Contact

The first source of confusion can come from the note that accompanies the L20-L30 (Dermatitis and eczema) code block. “Coders need to pay special attention to the note, which states that ‘In this block the terms dermatitis and eczema are used synonymously and interchangeably’,” says Jan Rasmussen, PCS, CPC, ACS-GI, ACS-OB, owner/consultant of Professional Coding Solutions in Holcombe, Wisconsin.

In fact, there is a clinical difference between the two, and many physicians will use the term atopic dermatitis as a synonym for eczema. If so, you would choose a code from L20.- (Atopic dermatitis), though some forms of the condition are codable to L30.- and other chapters of ICD-10 per the index.

Another source of confusion lies in the difference between using a code from L23.- (Allergic contact dermatitis) and L24.- (Irritant contact dermatitis). The two sound very much alike; however, irritant contact dermatitis is mostly confined to the area of skin affected by the contact, whereas allergic contact tends to affect a wider area.

As a coder, this means you must be hypervigilant while coding for the various conditions, as there are different codes for allergic- and irritant-contact dermatitis due to metals such as chromium and nickel (L23.0 and L24.81, respectively); cosmetics (L23.2 and L24.3, respectively); drugs in contact with skin (L23.3 and L24.4 respectively); dyes (L23.4 and L24.89, respectively); and other chemical products, such as cement, insecticide, plastic, and rubber (L23.5 and L24.5, respectively).

Coding caution: L23.3 and L24.4 both feature an additional code note that tells you to code for the drug using T36-T50 along with a fifth or sixth character of 5 in the case of adverse effects, if applicable.

2. Know That Unspecified Contact Dermatitis Isn’t What it Seems

Further confusion arises when you examine the
L25.- (Unspecified contact dermatitis) codes more closely. Here, the “unspecified” aspect of these codes does not mean the cause of the dermatitis is unknown.

Rather, it refers to the nature of the contact dermatitis rather than its cause. In fact, the code group contains a number of causal codes that are similar to the allergic- and irritant-contact dermatitis codes, including codes for dermatitis caused by cosmetics (L25.0), drugs in contact with skin (L25.1), dyes (L25.2), and chemical products like cement and insecticides (L25.3).

To add to the confusion, L25.5 (Unspecified contact dermatitis due to plants, except food) does not include nettle rash, which has its own code: L50.9 (Urticaria, unspecified). Fortunately, there is an Excludes1 note that accompanies L25.5 reminding you of the fact.

3. Know That Synonyms Can Hold the Key

Another really confusing aspect of dermatitis coding is the sheer number of conditions that either include dermatitis in their names or have dermatitis as a synonym. “This is where knowing the Includes and Excludes notes is especially useful,” Rasmussen points out.

Here is a partial list of some of them for quick reference:

• Juvenile dermatitis herpetiformis is a synonym for chronic bullous disease of childhood (CBDC) and is coded to L12.2
• Purulent dermatitis, septic dermatitis, and suppurative dermatitis are all synonyms for pyoderma and are coded to L08.0
• Dry skin dermatitis is a synonym for xerosis cutis and is coded to L85.3
• Stasis dermatitis is a synonym for venous insufficiency (chronic) (peripheral) and is coded to I87.2.

Coding alert: As you can see with these examples, not all dermatitis diagnosis codes are found in the L20-L30 code block of ICD-10. For example, per the Excludes1 note following I87.2, stasis dermatitis with a diagnosis of varicose veins of lower extremities is coded to I83.1- (Varicose veins of lower extremities with inflammation) and I83.2- (Varicose veins of lower extremities with both ulcer and inflammation).

The Bottom Line?

“The biggest problem I see is lack of detail from providers to code more specifically anything other than L30.9 [Dermatitis, unspecified] for dermatitis or eczema,” Rasmussen notes. “That’s because providers often only have enough information to document the symptoms of the skin problem, such as rash [R21], hives [L50.9], or skin inflammation [L08.9] rather than providing a more definitive diagnosis,” adds Sheri Poe Bernard, CPC, CRC, CDEO, CCS-P, author of the AMA book, Risk Adjustment Documentation and Coding.

“To infer more meaning to the terms would be to code in error, although I recommend that the provider be queried for a more definitive diagnosis if you believe the provider may be able to provide one,” Bernard adds.

“If you’re unsure, look up the terminology on the internet,” Rasmussen suggests. “You can also consult the government ICD-10-CM pdf files that are available, because they are easily searched for documented terms to validate diagnoses and codes,” adds Bernard. And the Centers for Disease Control (CDC) also has a search tool at  icd10cmtool.cdc.gov/?fy=FY2019.