Revenue Cycle Management in the Days of ICD-10: A Primer for Dermatology

ICD 10 codes for psoriasis, psoriatic arthritis, dermatitis and all things Dermatology-relatedContinuing our series on ICD-10-CM basics we are offering high-level primers to illustrate the differences on specific documentation requirements for various specialties. We will also give some samples of how ICD-9-CM codes common for those specialties compare to ICD-10-CM codes. Again, much of the material in these speciality-specific blog posts is based on guidelines and material published by CMS in its Road to 10 Series. There is a lot of questionable information and advice out there and we want to help improve the consistency and reduce the uncertainty by going to the source of regulations. We will summarize and consolidate to enhance readability and brevity. The application of ICD-10 documentation requirements and the common codes for Dermatology practice management is the focus of this post. In ICD-10-CM, there are three main categories of changes:

  • Definition Changes
  • Terminology differences
  • Increased specificity

Much of the increase in dermatology ICD-10 codes is driven by increased specificity for disease types.  Using psoriasis as an example, in ICD-9-CM there is only one code of 696.1 – that’s as specific as it gets. By contrast, in ICD-10, psoriasis is in the category of L40, which is then granulated (“broken down”) into numerous individual subtypes such as Psoriasis Vulgaris (L40.0),  Guttate Psoriasis (L40.4), and Pustular Psoriasis on the hands and feet (L40.3), just to name a few. ICD-10-CM Sample Coding for Psoriasis

  • Primary category: L (0-99, for diseases of the skin and subcutaneous tissue)
  • 2-digit category: 40 (Psoriasis)

So the primary code would be L40, which is then further specified (according to factors such as etiology, anatomic site, and other vital details) to create a final diagnosis code from the following possibilities:

L40.0 Psoriasis vulgaris
L40.1 Generalized pustular psoriasis
L40.2 Acrodermatitis continua
L40.3 Pustulosis palmaris er plantaris
L40.4 Guttate psoriasis
L40.5 Psoriasis, other
L40.50 Arthropathic psoriasis, unspecified
L40.51 Distal interphalangeal psoriatic arthropathy
L40.52 Psoriatic arthritis mutilans
L40.53 Psoriatic spondylitis
L40.54 Psoriatic juvenile arthropathy
L40.59 Other psoriatic arthropathy
L40.8 Other psoriasis
L40.9 Psoriasis, unspecified

Another example of increased specificity is for Atopic Dermatitis.  This incredibly vague diagnosis is coded in ICD-9-CM as 691.8, which more or less just tells someone that the diagnosis is some form of dermatitis that isn’t “diaper or napkin rash.”  In the ICD-10-CM language, however, there are a number of far more specific coding options. ICD-10-CM Sample Coding for Atopic Dermatitis

  • Primary category: L (0-99, disease of the skin and subcutaneous tissue)
  • 2-digit category: 20 (atopic dermatitis)

So the primary code would be L20, and must now be specified (according to etiology, anatomic site, and other vital details) to create a final diagnosis code from the following possibilities:

L20.0 Besnier's prurigo
L20.8 Other atopic dermatitis
L20.81 Atopic neurodermatitis
L20.82 Flexural eczema
L20.83 Infantile (acute) (chronic) eczema
L20.84 Intrinsic (allergic) eczema
L20.89 Other atopic dermatitis
L20.9 Atopic dermatitis, unspecified

ICD-10-CM also greatly reduces what often seems to be completely illogical code sharing between totally unrelated diagnoses. For example, with ICD-9-CM, even though Melasma and Solar Lentigines are two very different diagnoses, they both share the same code of 709.09. In fact, there are quite a few such “shared codes” in ICD-9-CM. With ICD-10-CM, most (but not all) unique conditions or lesions have their own code. Using those same diagnoses as an example, Melasma has its own code of L81.1 and Solar Lentigines have their own code of L81.4. In order to reflect this greater degree of detail, the codes are longer than ICD-9-CM codes to capture more data elements.  Depending on the diagnosis, there can be up to six or (rarely) even seven characters.  In dermatology, the vast majority of dermatology ICD 10 codes are going to be in the 4-6 character range, with the longest typically being the neoplasm codes. For example, consider the ICD-10-CM code for Squamous cell carcinoma (SCC) of the right eyelid which is code C44.122. One of the reasons that the neoplasm codes are so long is because laterality (whether the lesion or condition affects the right or left side) will be indicated in certain ICD-10-CM codes. In the example of SCC on the eyelid. The sixth character in the code for an SCC on an unspecified eyelid is ‘1’, while that of an SCC on the right eyelid is ‘2’, and one on the left eyelid is ‘9’. This is actually a common pattern seen throughout the ICD-10-CM neoplasm codes. Another unique feature of ICD-10-CM is that certain diagnoses will need to be described using more than one code. Take the category of ‘Abscesses, furuncles, and carbuncles’ as an example. When coding for an abscess, we’re asked to also provide a code for the causative bacteria. Finally, with ICD-10-CM there is greatly expanded coding that describes “situations and circumstances." These would include times when a) a person who may not be sick comes in for a specific reason, or when b) circumstances influence a person’s health status, but those circumstances aren’t an actual illness or injury. While the dermatology ICD-10 code expansion won’t affect dermatology nearly as much as it will a few other specialties, there are some examples of these types of codes for describing a visit for skin cancer screening (Z12.83), post-op nurse visits (Z48.817), or even when someone has a personal history of melanoma (Z85.820).  There will also now be a code to describe an “encounter for allergy testing” (Z01.82), which presumably might be used if your office does “patch” or RAST testing. An example of when the seventh character is likely to be relevant is repair of accidental lacerations.  For example, code S01.01 is Laceration of the scalp without a Foreign Body. At the top of the category, there are instructions that “The appropriate 7th character is to be added to each code from category S01″ – and then describes how ‘A’ will be used if this is the initial encounter, ‘D’ will be used if this is a follow-up related to the laceration, and ‘S’ would be used if this is a “sequela” of the laceration. That is, the patient is being seen for something else besides the laceration, but which was caused by the laceration. For example, the patient is coming a few weeks later asking for pain medicine because of the associated pain, but the laceration itself has already been treated and is itself no longer an issue. If this is an initial visit, if we simply add the ‘A’ to the end, that only makes 6 characters, when a 7th character is required. That’s where the “placeholder X” should be used.  Anytime 7 characters are required but the sixth digit is not relevant, the letter ‘X’ is used as a placeholder. So in this example, letter ‘X’ would be added as a placeholder with ‘A’ as the 7th character indicating that this is the initial encounter.  The final code would then be S01.01XA.

Comparison of ICD-9-CM and ICD-10-CM Codes for Dermatology


706.1 Acne, other


L70.0 Acne vulgaris
L70.1 Acne conglobata
L70.3 Acne tropica
L70.4 Infantile acne
L70.5 Acne excoriee des jeunes filles
L70.8 Acne, other
L70.9 Acne, unspecified
L73.0 Acne keloid


709.09 Dyschromia, other


L57.3 Poikiloderma of civatte
L81.1 Chloasma
L81.6 Disorders of diminished melanin formation
L81.0 Postinflammatory hyperpigmentation
L81.2 Freckles
L81.3 Cafe au lait spots
L81.4 Melanin hyperpigmentation, other
L81.5 Luekoderma, not elsewhere classified
L81.7 Pigmented purpuric dematosis
L81.8 Specified disorders of pigmentation, other


681.00 Cellulitis and abscess, unspecified


L02.511 Cutaneous abscess of right hand
L02.512 Cutaneous abscess of left hand
L02.519 Cutaneous abscess of unspecified hand
L03.011 Cellulitis of right finger
L03.012 Cellulitis of left finger
L03.019 Cellulitis of unspecified finger
L03.021 Acute lymphangitis of right finger
L03.022 Acute lymphangitis of left finger
L03.029 Acute lymphangitis of unspecified finger


Please bear in mind these are only the most common dermatology ICD10 codes. Should you need more, please feel free to visit our comprehensive ICD-10 database.