R23.9 ICD-10-CM Code: Unspecified skin changes

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for R23.9 in the official ICD-10-CM tabular list, quoted as published.

Source: CMS/CDC — ICD-10-CM Tabular ListRelease: FY2026Effective: October 1, 2025

Notes without a marker are published on R23.9 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for R23.9

MedCoder structured workflow — derived from this code’s own official record

Before you code R23.9

1. Check whether an established diagnosis that explains this sign or symptom is documented. If one is, review whether the documented diagnosis changes the coding pathway: a symptom that is integral to a confirmed diagnosis is not reported separately, while one not routinely associated with it may be. Signs and symptoms are reported when no definitive diagnosis is established (Guidelines I.B.4, I.B.5, I.B.6, I.C.18.b).

   Guide: Symptom code vs confirmed diagnosis →

2. Unspecified does not mean incorrect. When the record gives no greater specificity, R23.9 may be the appropriate code. Check the record for detail that supports a more specific sibling. An unspecified code is for records that do not provide the detail a more specific code needs; a query, not an assumption, is the route to specificity (Guidelines I.A.9.b, I.B.18).

   ReviewR23.0, R23.1, R23.2, R23.3, R23.4, R23.8

   See the relationships section · Guide: Other vs unspecified (NEC vs NOS) →

Choose the right path

1. Is an established diagnosis that explains this sign or symptom documented?
   Yes → Review whether the documented diagnosis changes the coding pathway: a symptom integral to it is not reported separately.
   No → Continue — the sign or symptom code stands when no definitive diagnosis is established.
2. Does the record document the detail a more specific sibling code needs?
   Yes → Review the specific siblings in this subcategory.
   No → Continue — R23.9 is appropriate when the documentation goes no further.

   ReviewR23.0, R23.1, R23.2, R23.3, R23.4, R23.8

Consider R23.9. Then confirm the code is valid for the date of service in the Verify section.

Documentation check

The provider’s diagnostic statement

Codes are assigned from the provider’s documented diagnosis, not from clinical criteria, test values or a medication list (Guidelines I.A.19).

Any detail beyond this code’s title

What the record states that a more specific sibling code would capture — or its absence, which itself supports the unspecified code.

Official instructions as workflow

• Excludes2 — not part of R23.9(1 note)

  Coding workflow: The conditions named in this note are not included in R23.9. When the record documents both, both may be reported; the note is a boundary, not a prohibition.

  See the official tabular notes · Guidelines I.A.12.b

Coding decision scenarios

Pattern scenarios for this code’s structure — decision rules, not clinical cases

Every row is derived from this code’s own record — its title, tabular notes, 7th-character family and same-category siblings — with fixed MedCoder wording; nothing is inferred about a patient. The official notes and guideline text are in the sections each row links to, and they control.

Indexed Clinical Terms (4)

Official source data — entries quoted as published, in the Index’s own lookup phrasing

Clinical term phrases from the official ICD-10-CM Index to Diseases and Injuries that map to this code. These are alphabetic-index entries shown as the Index writes them — lookup phrasing, not necessarily the wording of a final diagnosis.

• Change (s) (in) (of), skin
• Symptoms NEC, involving, skin and integument
• Symptoms NEC, skin and integument NEC
• Symptoms NEC, subcutaneous tissue NEC

Don’t confuse R23.9 with…

MedCoder analysis — pairs from this code’s official notes, distinctions written by MedCoder

The codes most likely to be picked instead of R23.9 — named in its own official notes, or sharing its laterality or encounter family — with what separates them and which documentation moves the case. Each links to the full comparison.

• N64.4— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of symptoms relating to breast adds N64.4; it is not part of this code and both may be reported when both are documented.

  Full comparison: R23.9 vs N64.4 →

• N64.5— Excludes2 relationship (Informational)

  Distinct conditions — both may be reported.

  A distinct condition — both may be reported when both are documented.

  What moves you there: Documentation of symptoms relating to breast adds N64.5; it is not part of this code and both may be reported when both are documented.

  Full comparison: R23.9 vs N64.5 →

Relationships are read from this code's own official notes, its laterality siblings and its encounter family; the wording of each distinction is MedCoder editorial, and the documentation named in each “what moves you there” line is the official note phrase or sibling title itself. Source: CMS ICD-10-CM tabular instructional notes; ICD-10-CM Official Guidelines, Section I.A.12.a.

Verify Before Coding

• No Medicare Code Editor or MS-DRG Definitions Manual restrictions apply to this code.

From the code registry, the Medicare Code Editor, and the MS-DRG Definitions Manual. Check it against a full claim in Claim Check.

Relationships & Classification

MedCoder structured relationships — computed from published CMS and AHRQ datasets

MS-DRG Grouper Relationships (FY2026)

Potential MS-DRG participation — not a DRG assignment.

FY2026 MS-DRG: not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity for that release.

Named in the grouper logic of 2 MS-DRGs: DRG 606 (MDC 09), DRG 607 (MDC 09).

From the CMS MS-DRG Definitions Manual (Appendices B and C). Actual DRG assignment depends on the complete claim.

Clinical classification (AHRQ CCSR):SYM014 — Skin/Subcutaneous signs and symptoms (default).

Clinical Classifications Software Refined (CCSR) for ICD-10-CM Diagnoses. Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality.

Related Codes

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Skin/Subcutaneous signs and symptoms).

R20.9 — Unspecified disturbances of skin sensation, R21 — Rash and other nonspecific skin eruption, R22.0 — Localized swelling, mass and lump, head, R22.1 — Localized swelling, mass and lump, neck, R22.2 — Localized swelling, mass and lump, trunk, R22.30 — Localized swelling, mass and lump, unspecified upper limb, R22.31 — Localized swelling, mass and lump, right upper limb, R22.32 — Localized swelling, mass and lump, left upper limb, R22.33 — Localized swelling, mass and lump, upper limb, bilateral, R22.40 — Localized swelling, mass and lump, unspecified lower limb, R22.41 — Localized swelling, mass and lump, right lower limb, R22.42 — Localized swelling, mass and lump, left lower limb, R22.43 — Localized swelling, mass and lump, lower limb, bilateral, R22.9 — Localized swelling, mass and lump, unspecified, R23.0 — Cyanosis, R23.1 — Pallor, R23.2 — Flushing, R23.3 — Spontaneous ecchymoses, R23.4 — Changes in skin texture, R23.8 — Other skin changes, +5 more

Same Index main term, other category

The ICD-10-CM Index to Diseases and Injuries files this code under the main terms “Symptoms NEC”, “Change”; these codes share that main term but sit in a different category of the Tabular List.

M46.1 — Sacroiliitis, not elsewhere classified (inflammatory, sacroiliac), M53.3 — Sacrococcygeal disorders, not elsewhere classified (sacroiliac joint), N05.0 — Unspecified nephritic syndrome with minor glomerular abnormality (minimal), N64.59 — Other signs and symptoms in breast (breast NEC), N95.1 — Menopausal and female climacteric states (menopausal), R09.89 — Other specified symptoms and signs involving the circulatory and respiratory systems (involving, chest NEC), R10.20 — Pelvic and perineal pain unspecified side (pelvis NEC, female), R19.4 — Change in bowel habit (bowel habit), R19.8 — Other specified symptoms and signs involving the digestive system and abdomen (involving, pelvis NEC), R20.8 — Other disturbances of skin sensation (sensory), R29.818 — Other symptoms and signs involving the nervous system (involving, nervous system, specified NEC), R29.898 — Other symptoms and signs involving the musculoskeletal system (involving, musculoskeletal system, specified NEC), R29.90 — Unspecified symptoms and signs involving the nervous system (involving, nervous system), R29.91 — Unspecified symptoms and signs involving the musculoskeletal system (involving, musculoskeletal system), R39.9 — Unspecified symptoms and signs involving the genitourinary system (involving, urinary system), R41.0 — Disorientation, unspecified (involving, awareness, disorientation), R41.4 — Neurologic neglect syndrome (involving, awareness, neurologic neglect syndrome), R41.81 — Age-related cognitive decline (involving, awareness, senile cognitive decline), R41.82 — Altered mental status, unspecified (mental status), R41.83 — Borderline intellectual functioning (involving, awareness, borderline intellectual functioning), +46 more

Lab tests where this diagnosis supports Medicare coverage (NCD)

Medicare's National Coverage Determination (NCD) program lists this diagnosis as medical justification for these lab tests.

Thyroid Stimulating Hormone (TSH)

Contextual Map

Every relationship of R23.9 in one view: hierarchy, official tabular instructions in both directions, clinical classification, risk adjustment, MS-DRG participation, index terms and change history — each edge carrying the CMS source it derives from.

Hierarchy

• R00-R99 — Chapter 18: Symptoms, Signs and Abnormal Clinical and Laboratory Findings, Not Elsewhere Classified (R00-R99) (R00-R99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R20-R23 — Symptoms and signs involving the skin and subcutaneous tissue[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Clinical classification (CCSR)

• SYM014 — Skin/Subcutaneous signs and symptoms[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

MS-DRG Grouper

• DRG 606 — MINOR SKIN DISORDERS WITH MCC[MS-DRG]: “MINOR SKIN DISORDERS WITH MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 607 — MINOR SKIN DISORDERS WITHOUT MCC[MS-DRG]: “MINOR SKIN DISORDERS WITHOUT MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026

MDC crossing

• MDC 09 — Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast[MDC crossing]: “Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast — the grouper's crossing between diagnoses and procedures: a principal diagnosis sets the MDC, and same-MDC procedures move the stay to its surgical DRGs. 7,376 same-MDC procedures group here; browse them on the MDC page.”— CMS MS-DRG Definitions Manual · FY2026

Index entries

• Change (s) (in) (of), skin[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Symptoms NEC, involving, skin and integument[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Symptoms NEC, skin and integument NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
• Symptoms NEC, subcutaneous tissue NEC[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

• R23 — Other skin changes[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R23.0 — Cyanosis[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R23.1 — Pallor[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R23.2 — Flushing[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R23.3 — Spontaneous ecchymoses[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R23.4 — Changes in skin texture[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• R23.8 — Other skin changes[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Change history

• FY2016 — In the code set at ICD-10-CM adoption [Change history]— CMS release files (code change ledger) · icd10cm-fy2016

Sources for this page

Codes, titles, notes, index terms and mappings on this page are transcribed from the datasets below. Relationships MedCoder computed and text MedCoder wrote are labelled where they appear.

Code, title, tabular notes and index terms Official source data

CMS/CDC ICD-10-CM FY2026 tabular list, index and tables, effective October 1, 2025 Release, file and checksum · Publisher’s page

Claim edits Official source data

CMS Definitions of Medicare Code Edits — v43.1 (April 2026) Release, file and checksum · Publisher’s page

Inpatient payment groups Official source data

CMS MS-DRG Definitions Manual (incl. Appendix B diagnosis index, Appendix C CC/MCC list, Appendix E procedure index) and IPPS Final Rule tables — v43 Release, file and checksum · Publisher’s page

Change history and date-of-service validity Official source data

CMS ICD-10-CM release addenda, ingested release by release into the change ledger Release, file and checksum · Publisher’s page

Comparisons, relationships and the contextual map MedCoder structured relationship

Computed by MedCoder from the tabular notes and tables above; every derived relationship is marked as derived where it appears

Summary and FAQ answers MedCoder explanation

Written by MedCoder to explain the sources above: drafted with AI assistance, checked by a person against the release files, and labelled as MedCoder text where it appears. Not official text.

Labels on this page: Official source data · MedCoder structured relationship · MedCoder explanation. How to read the labels · All data sources and release dates

Nearest Codes in This Family

Official ICD-10-CM classifications closest to R23.9 in its code family, with their registry titles.

• R23 — Other skin changes
• R23.0 — Cyanosis
• R23.1 — Pallor
• R23.2 — Flushing
• R23.3 — Spontaneous ecchymoses
• R23.4 — Changes in skin texture
• R23.8 — Other skin changes

View all codes in the R23 family