2026 ICD-10-CM Diagnosis Code L40.1Generalized pustular psoriasis

ICD-10-CM Codes›L00–L99›L40-L45›L40

ICD-10-CM L40.1
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

L40.1 is a billable ICD-10-CM diagnosis code for generalized pustular psoriasis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 606 through 607. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified inflammatory condition of skin.

Code Identity

ICD-10-CM Code
L40.1
Billable Status
Yes — Valid for Submission
Code Describes
Generalized pustular psoriasis
Short Description
Generalized pustular psoriasis
Same as the full description in the CMS dataset.
Parent Code
L40
Psoriasis

Code Classification

ChapterL00–L99Diseases of the skin and subcutaneous tissue
SectionL40-L45Papulosquamous disorders
CategoryL40Psoriasis
This CodeL40.1Generalized pustular psoriasis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Acute blistering eruption of skin
  • Acute generalized pustular flare of preexisting plaque psoriasis
  • Acute generalized pustular psoriasis de novo
  • Acute pustular skin eruption
  • Bullous eruption
  • Circinate and annular pustular psoriasis
  • Exacerbation of psoriasis
  • Exanthematous disorder
  • Generalized pustular psoriasis
  • Generalized pustular psoriasis of pregnancy
  • Generalized pustular psoriasis, exanthematous type
  • Infantile pustular psoriasis
  • Localized pustular psoriasis
  • Plaque psoriasis
  • Plaque psoriasis with pustules
  • Pustular psoriasis
  • Vesicular eruption

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Impetigo herpetiformis
  • Von Zumbusch's disease

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Impetigo(any organism) (any site) (circinate) (contagiosa) (simplex) (vulgaris)
      • herpetiformis
    • Impetigo(any organism) (any site) (circinate) (contagiosa) (simplex) (vulgaris)
      • herpetiformis
        • nonobstetrical
    • Psoriasis
      • pustular (generalized)
    • Von Zumbusch's disease

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR SKN002
Other specified inflammatory condition of skin
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Generalized Pustular Psoriasis

    a genetically heterogenous autoinflammatory condition characterized by sterile non-follicular pustules over wide areas of the body. it is a rare and severe form of psoriasis, and may result in death if not treated.

Patient EducationClinical

Psoriasis

Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. You usually get the patches on your elbows, knees, scalp, back, face, palms and feet, but they can show up on other parts of your body. Some people who have psoriasis also get a form of arthritis called psoriatic arthritis.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert L40.1 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
694.3 Impetigo herpetiformis
Approximate The match is approximate rather than exact.
ICD-9-CM
696.1 Other psoriasis
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About L40.1Overview

Is L40.1 (Psoriasis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report generalized pustular psoriasis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does L40.1 group to?

When generalized pustular psoriasis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 606, 607, with relative weights from 0.9064 to 1.5132 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of L40.1?

Under the General Equivalence Mappings, generalized pustular psoriasis converts to ICD-9-CM 694.3 (impetigo herpetiformis) and 696.1 (other psoriasis). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.