2026 ICD-10-CM Diagnosis Code S90.425DBlister (nonthermal), left lesser toe(s), subsequent encounter

ICD-10-CM Codes›S00–T88›S90-S99›S90

ICD-10-CM S90.425D
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

S90.425D is a billable ICD-10-CM diagnosis code for blister (nonthermal), left lesser toe(s), subsequent encounter. The 7th character D marks it as a subsequent encounter code, used during routine care in the healing or recovery phase. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 949 through 950. The code is exempt from POA reporting. Coders also document this condition as blister of foot with infection. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Superficial injury; contusion, subsequent encounter.

Code Identity

ICD-10-CM Code
S90.425D
Billable Status
Yes — Valid for Submission
Code Describes
Blister (nonthermal), left lesser toe(s), subsequent encounter
Short Description
Blister (nonthermal), left lesser toe(s), subs encntr
Parent Code
S90.425
Blister (nonthermal), left lesser toe(s)

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS90-S99Injuries to the ankle and foot
CategoryS90Superficial injury of ankle, foot and toes
This CodeS90.425DBlister (nonthermal), left lesser toe(s), subsequent encounter

Present on Admission (POA)Billing

S90.425D is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Blister of foot with infection
  • Blister of toe with infection
  • Left foot blister with infection
  • Left lesser toe blister with infection
  • Traumatic blister of left foot
  • Traumatic blister of left lesser toe
  • Traumatic blister of lesser toe
  • Traumatic blister of toe

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Superficial injury of ankle, foot and toes (S90). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2026, published by CMS and the National Center for Health Statistics.

Clinical ClassificationClinical

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

CCSR INJ054
Superficial injury; contusion, subsequent encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Clinical InformationClinical

  • Herpes Labialis

    herpes simplex, caused by type 1 virus, primarily spread by oral secretions and usually occurring as a concomitant of fever. it may also develop in the absence of fever or prior illness. it commonly involves the facial region, especially the lips and the nares. (dorland, 27th ed.)

  • Blister

    visible accumulations of fluid within or beneath the epidermis.

Patient EducationClinical

Blisters

Blisters are fluid-filled sacs on the outer layer of your skin. They form because of rubbing, heat, or diseases of the skin. They are most common on your hands and feet.

The full article covers:

  • What are blisters?
  • What causes blisters?
  • What are the treatments for blisters?
  • Can blisters be prevented?

Read the full article at MedlinePlus

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

Convert S90.425D to ICD-9-CMHistory

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

ICD-9-CM
V58.89 Other specfied aftercare
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 S90.425DOverview

Is S90.425D (Blister (nonthermal), left lesser toe(s)) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report blister (nonthermal), left lesser toe(s), subsequent encounter on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What does the 7th character D in S90.425D mean?

The final character D marks a subsequent encounter: use it for routine care while the blister (nonthermal), left lesser toe(s) is healing, after active treatment has ended.

What MS-DRG does S90.425D group to?

When blister (nonthermal), left lesser toe(s), subsequent encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 949, 950, with relative weights from 0.6277 to 1.1897 depending on complications. Higher weights mean higher Medicare reimbursement.

Is S90.425D exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for blister (nonthermal), left lesser toe(s), subsequent encounter on inpatient claims.

What is the ICD-9 equivalent of S90.425D?

Under the General Equivalence Mappings, blister (nonthermal), left lesser toe(s), subsequent encounter converts to ICD-9-CM V58.89 (other specfied aftercare). The mapping is approximate, so confirm the match fits the documentation.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.