Psoriasis ICD 10 Code

Refresher: What are ICD-10 codes?

ICD-10 stands for the International Classification of Diseases, having entered its 10th revision [1]. It is a cataloging system for various medical conditions to track diagnostic data, healthcare outcomes, and many statistics. The ICD-10-CM is a US-specific clinical modification (hence the abbreviation) that is applied to the ICD-10 for use across US healthcare organizations [2].

The updated ICD-10-CM code set has orders of magnitudes more codes than the ICD-9 version, and this helps medical professionals and coders provide accurate diagnoses. The ICD-10-CM codes are also utilized for billing purposes and processing.

The ICD-9 code set only contains about 13,000 codes compared to about 68,000 for the ICD-10 version [3]. This allows for more specificity and makes it easier for medical coders to measure health outcomes for patients.

Some of the biggest advantages of using the ICD-10-CM code set are the following features:

  • More details to account for the medical condition's severity, complexity, and location
  • Consistent terminology of medical disease
  • Adding more concepts to the code set that are not found in the previous iteration

Note that the ICD-10-PCS is used for the purposes of tracking health interventions taken by medical professionals. It has over 87,000 codes and is only applicable to inpatient hospital settings in the US [4].

What is the ICD 10 code for Psoriasis?

For psoriasis, the general ICD-10 code is L40 (psoriasis), a medical condition characterized where the skin is covered with red patches and white scales.

Psoriasis ICD 10 code: L40

Psoriasis ICD code L40 lookup

Below is a table of the ICD 10 psoriasis codes for chronic diseases of the skin covered with red patches and white scales, which are classified under L40, “psoriasis” [5].

L40: Psoriasis

psoriasis ICD code

Studies show that psoriasis has affected an estimated 7.55 million US adults, which accounts for nearly 2% of the people living in the country [6]. Most people living with psoriasis have white skin, but the medical condition has been found in people of all races. An increasing body of studies shows that psoriasis may be more common in people of color than previously thought.

With that said, the annual incidence of psoriasis has been on the rise, having almost doubled between the years 1970s and 2000 [7]. Scientists struggle to understand this increase in incidence, and could include various factors.

With that said, psoriasis does not affect life expectancy. However, studies show that psoriasis can increase one’s odds of contracting other life-threatening diseases such as lung cancer, lymphoma, and non-melanoma skin cancer [8]. Some conditions, such as HIV and AIDs, can weaken the immune system and increase one’s risk of developing psoriasis.

It is worth mentioning that it can be difficult to diagnose psoriasis because the condition looks very similar to other skin problems, such as eczema. Make sure to discuss your symptoms with a doctor if you believe you have psoriasis. There is a large variance in the symptoms of psoriasis depending on its type.

Here are a few signs and symptoms of psoriasis worth discussing:

  • Plaque psoriasis is characterized by dry, raised, and itchy skin patches covered with scales
  • Nail psoriasis mostly affects toenails and fingernails, causing abnormal nail growth
  • Guttate psoriasis mostly affects younger adults and children, creating small drop-shaped scaling spots on the arms and legs
  • Inverse psoriasis mostly affects the skin folds of the buttocks, breasts, and groin
  • Pustular psoriasis is relatively rare, and causes pus-filled blisters that can occur in widespread patches
  • Erythrodermic psoriasis is a rare type of psoriasis that can cover the entire body with a peeling rash

It should be noted that many people who are prone to psoriasis may be asymptomatic until the disease is triggered by an epiretinal factor. Common triggers for psoriasis include infections (such as strep throat) and the weather, especially cold and dry spells.

Diagnosing psoriasis can be challenging. However, most dermatologists should be able to identify the skin disease by examining the location, distribution, size, and shape of lesions. During a physical exam, the doctor may ask about your symptoms and medical history, including whether someone in your family has been diagnosed with the skin disease.

In some cases, the dermatologist may require more information about the skin and will usually require a skin biopsy. The biopsy test will be sent to a pathologist for examining skin cells under a microscope to confirm psoriasis. A skin biopsy may be performed with the help of a device to puncture the skin and remove a small tissue sample. It takes about a week for the results of a skin biopsy to become available.

Types of Psoriasis Coded under L40

The ICD 10 code L40 does not specify the subtype of psoriasis. An L40 code can be used for psoriasis of any kind:

  • Acrodermatitis continua of hallopeau
  • Dermatitis repens
  • Palmoplantar pustulosis
  • Pustular psoriasis of the soles and/or palms
  • Psoriasis, guttate
  • Psoriasis arthritis
  • Psoriasis with arthropathy
  • Psoriatic arthritis with distal interphalangeal joint involvement
  • Psoriatic arthritis with spine involvement
  • Juvenile psoriatic arthritis
  • Flexural psoriasis
  • Plaque psoriasis
  • Nail psoriasis
  • Inverse psoriasis
  • Erythrodermic psoriasis

In other words, acrodermatitis continua of hallopeau ICD 10, psoriatic arthritis with distal interphalangeal joint involvement ICD 10, and psoriasis with arthropathy ICD 10 codes could all be L40 if they are determined to be a chronic skin disease with red patches and white scales. As a concrete example, a patient diagnosed with flexural psoriasis, also known as inverse psoriasis that affects the body folds, would be coded with L40.8.

There are several advantages of upgrading from the ICD-9 to the upgraded ICD-10 coding system. The ICD-10 provides more specificity and details to help doctors diagnose a medical condition. This makes it easier to administer more effective treatments to patients.

The ICD-10 code set aims to make the storage of medical histories easier for patients in an organized and consistent manner. This would allow physicians in various healthcare organizations to know if the skin disorder is psoriasis or a similar medical condition.

The ICD-10 code set does have a few disadvantages that should be discussed. Firstly, it can be very difficult for organizations in the US to make the transition to the ICD-10 from ICD-9. Service providers often charge a premium for updating to the new system. This isn’t the end of their problems though. Healthcare providers, including medical coders, will be required to upgrade their certification to be able to use the ICD-10-CM code set. This means more time spent studying and taking exams, all of which can be fairly expensive to medical professionals.

In addition, switching to ICD-10-CM can also take a long time to adapt to. During this transitory period, healthcare organizations will notice a small dip in productivity that could deprive them of their revenue.

It should be noted that the ICD-10-CM code set can be difficult to use because of its accuracy. Although healthcare professionals can use the code set to accurately identify the medical donations, on the other hand, there is a small chance that the disease could be miscoded. This could potentially expose the patient to an incorrect medical procedure that not only exacerbates their symptoms and exposes them to undesirable side effects but allows the disease to go untreated.

Similar medical conditions excluded from ICD-10 L40

  • Pemphigoid (L12)
  • Impetigo (L01)
  • Eczema
  • Seborrheic dermatitis
  • Skin cancer
  • Keratosis pilaris
  • Allergic contact dermatitis
  • Ringworm
  • Pityriasis rosea

Eczema, in particular, can be confused with psoriasis because it also causes redness and inflammation. However, eczema usually occurs inside the elbow and on the backs of the knees. Psoriasis, on the other hand, is more commonly found over the elbows and knees.

Rosacea also shares similar symptoms with psoriasis. It is a type of acne that causes redness from pus-filled pimples on the face. It can get worse over time and shares similar triggers with psoriasis, including changes in weather and stress.


The ICD-10 code for psoriasis is L40. The coding system allows medical professionals to classify soft tissue disorders and provide detailed diagnostics for psoriasis. The coding system does not apply to all skin disorders and lesions. The nature of the medical condition is such that it can be easily confused with any other skin disorder that has overlapping symptoms.

This is why you discuss your symptoms of psoriasis with a doctor for verification. The information provided in this article is only meant to be used for reference purposes and should not be taken as professional medical advice. You should also direct any question you have about ICD-10 L40 for psoriasis and other skin diseases to a healthcare professional.