Coding for Psoriasis – ICD 9 to ICD 10

Touseef Riaz

September 24, 2021

Coding for 696.1

When it comes to reporting and coding for dermatology-related conditions, the process is more complex than you would have imagined, especially when you have to crosswalk between code sets.

Psoriasis is one of the most prevalent autoimmune diseases in the US, with over 8 million cases reported annually. The process of coding for psoriasis can be quite daunting, given the transition from ICD 9 to ICD 10. In this article, we discuss the different types of psoriasis that a medical health provider/dermatologist can encounter and the corresponding ICD 10 codes for them. 

ICD-10 Code for 696.1 Psoriasis

In contrast to the ICD-9 code for psoriasis which is 696.1, the ICD 10 code for the condition describes it in more specificity. In ICD-9, there was only one code representing psoriasis i.e. 696.1, whereas there are multiple ICD-10 codes that correspond to the various subtypes that fall under the category L40. The L defines that this is the primary category for diseases of the skin and tissue. While the next two digits 40 define psoriasis.

Following are the ICD-10 codes which are converted approximately from ICD-9 696.1:

  • L40.0 Psoriasis vulgaris
  • L40.1 Generalized pustular psoriasis
  • L40.2 Acrodermatitis continua
  • L40.3 Pustulosispalmariserplantaris
  • 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 another psoriatic arthropathy
  • L40.8 Another psoriasis
  • L40.9 Psoriasis, unspecified
  • L41 Parapsoriasis
  • L41.0 Pityriasislichenoidesetvarioliformisacuta
  • L41.1 Pityriasislichenoideschronica
  • L41.3 Small plaque parapsoriasis
  • L41.4 Large plaque parapsoriasis
  • L41.5 Retiformparapsoriasis
  • L41.8 Otherparapsoriasis
  • L41.9 Parapsoriasis, unspecified

Approximate conversion from ICD-9 to ICD-10 requires clinical interpretation to arrive at the most appropriate code that fits the specific situation.

Outsourcing these processes to a trustworthy medical company like UControl Billing can help you stay updated with the current billing and coding rules, ensure the payment process is smooth and everything is properly documented for use as administrative data.

What is Psoriasis?

Psoriasis is an autoimmune disease affecting the skin. This means that the immune system, instead of protecting it, harms the body and skin. The condition causes your skin to develop scaly patches that are painful and itchy. The patches have the tendency to appear and disappear with time.

There are multiple types of psoriasis, and it is possible for a person to have more than one type. Below are the different types of psoriasis:

Plaque Psoriasis

This is the most common type, making up as much as 80 percent of the total cases of psoriasis. Plaque psoriasis causes inflamed patches that make the skin appear red and sore. A whitish-silver scaling covers the patches, which are also called plaques, hence the name.

Guttate Psoriasis

Often occurring in childhood, this type of psoriasis is characterized by small pink spots that commonly appear on the arms, legs, and torso. Unlike plaque psoriasis, there is no scaling in guttate so the spots are rarely thick.

Pustular Psoriasis

Pustular Psoriasis occurs more commonly in adults. It is characterized by areas of inflamed skin with white, pus-filled blisters that can be painful to the touch. This type is typically found in localized parts of the body, such as the feet or hands.

Inverse psoriasis

This type of psoriasis develops under the breasts, armpits, or groin, causing bright areas of shiny, red inflamed skin.

What is the ICD?

ICD, short for International Classification of Diseases, is the global standard for reporting health conditions and diseases, as well as the identification of health trends and statistics. The ICD contains tons of codes pertaining to disorders, injuries, diseases, and other health conditions which are presented in a hierarchical and comprehensive way.

The first edition of the ICD was adopted in 1893. Since then, it has seen many revisions to reflect the advancements in health sciences. Today, the ICD is in its tenth edition, which was endorsed in May 1990. The ICD 10 effectively replaced the previous ICD 9 on September 1, 2015. All claims for medical services rendered after that are mandated to follow the codes set forth in the ICD 10.

Crosswalking Between ICD 9 and ICD 10

One of the biggest challenges of the transition from ICD 9 to ICD 10 involves the crosswalking between the two code sets, incorporating numerous codes. Crosswalk is the process of translating or mapping a particular code from one code set to a code or multiple codes from another code set. More and more work has been done on crosswalking to make the task of transitioning to ICD 10 easier for medical billers and coders.

It is important for healthcare providers as well to understand crosswalking during the transition phase, so as to learn which codes from the ICD-10 will be used in place of the previous ICD-9 code, as there is not always an exact match between the two code sets. Such is the case when crosswalking between the ICD 9 and ICD 10 code for psoriasis, which we will further discuss in the next section.

The National Center for Health Statistics (NCHS) came up with a system called the General Equivalence Mappings or GEMs to easily crosswalk between different ICD 9 and ICD 10. GEMs consist of data files containing a list of ICD 9 and ICD 10 codes as well as the attributes required for successful mapping between the two. You can either map ICD-9 codes to ICD 10, called forward mapping, or map the ICD 10 codes to ICD 9 using backward mapping.


Over the last few years, there has been a steady increase in Medicare and private insurer audits of medical records relating to psoriasis and other dermatological conditions. It is important, therefore, to have accurate and detailed documentation to avoid any unnecessary scrutiny. The task can be daunting given the transition to the ICD 10 as well as the fact that the code set gets updated frequently.

Partnering with an established medical coding and billing company such as control Billing can ensure for your organization that the reporting and coding of all services are done error-free, paving the way for optimal and timely reimbursement.

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