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L58.9 ICD-10-CM Code: Radiodermatitis, unspecified

Billing Status: YES. This is a valid, specific, and billable ICD-10-CM reference.

Coding at a Glance

Tabular directives
1 use-additional code

Inpatient Payment Groups (MS-DRG)

Potential MS-DRG participation — not a DRG assignment.

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43, Appendix B.

  • MS-DRG 606 — MINOR SKIN DISORDERS WITH MCC (MDC 09)
  • MS-DRG 607 — MINOR SKIN DISORDERS WITHOUT MCC (MDC 09)

A diagnosis appearing in a group's logic does not by itself determine the DRG assigned to a stay; the grouper uses the full claim.

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for L58.9 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 L58.9 itself; “inherited from” names the category or block whose note applies here.

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • Use additional code to identify the source of the radiation (W88, W90)

Source: inherited from L58

Coder workflow for L58.9

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

Before you code L58.9

  1. Unspecified does not mean incorrect. When the record gives no greater specificity, L58.9 may be the appropriate code. Check the record for detail that supports a more specific sibling — in this subcategory the siblings differ by acute versus chronic. 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).

    ReviewL58.0, L58.1

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

Choose the right path

  1. Does the record document the detail a more specific sibling code needs?
    Yes → Review the specific siblings in this subcategory.
    No → Continue — L58.9 is appropriate when the documentation goes no further.

    ReviewL58.0, L58.1

Consider L58.9. Then work the Use Additional Code note, and 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).
Acuity
Acute or chronic as documented; when both are documented and separate codes exist, both are reported with the acute code first (Guidelines I.B.8).
The conditions the Use Additional Code note names
Reported with this code when documented; a conditional instruction (“if applicable”, “if known”) applies only when the record supports it.
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

  • Use Additional Code — after identifying L58.9(1 note)

    Coding workflow: Check whether the documentation supports the additional code(s) the note names, and report them with L58.9 when it does. Where the instruction is conditional (“if applicable”, “if known”), it applies only when the record documents the condition.

    ReviewW88, W90

    See the official tabular notes · Guidelines I.A.13

Coding decision scenarios

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

Documentation: The provider documents the condition in the terms of this code’s title and records no further detail.

Coding question: Is a more specific sibling code supportable?

Path: Review the specific siblings in this subcategory and what each requires the record to state.

Reason: A more specific code needs documentation of the distinguishing element; without it the unspecified code is appropriate, and a provider query is the route to specificity (Guidelines I.A.9.b, I.B.18).

ReviewL58.0, L58.1

Documentation: A condition the Use Additional Code note names is documented.

Coding question: Is a second code reported with L58.9?

Path: Review the Use Additional Code note and the code it names.

Reason: The additional code is reported when the record documents the condition; a conditional instruction applies only when its condition is met (Guidelines I.A.13).

ReviewW88, W90

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.

Code Overview

Radiodermatitis, unspecified is a billable ICD-10-CM diagnosis code (L58.9).

MedCoder summary Summary composed by MedCoder from this code's official ICD-10-CM record. The tabular instructional notes themselves appear verbatim below.

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.

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

Other codes that name L58.9 or its code family, from the CMS ICD-10-CM tabular instructional notes. Tabular-note edges are stored at the code family level that carries each note.

Referenced by 3 Excludes1 notes across 2 chapters: K13.0 — Diseases of lips (via L58.-), T66 — Radiation sickness, unspecified (via L58.-), T67 — Effects of heat and light (via L58.-).

These codes’ tabular lists mark this diagnosis as mutually exclusive — not reported together unless the conditions are documented as unrelated.

Referenced by 14 Excludes2 notes across 3 chapters: L20 — Atopic dermatitis (via L58.-), L20-L30 — Dermatitis and eczema (L20-L30) (via L58.-), L21 — Seborrheic dermatitis (via L58.-), L22 — Diaper dermatitis (via L58.-), L23 — Allergic contact dermatitis (via L58.-), L24 — Irritant contact dermatitis (via L58.-), L25 — Unspecified contact dermatitis (via L58.-), L26 — Exfoliative dermatitis (via L58.-), L27 — Dermatitis due to substances taken internally (via L58.-), L28 — Lichen simplex chronicus and prurigo (via L58.-), L29 — Pruritus (via L58.-), L30 — Other and unspecified dermatitis (via L58.-), T20-T32 — Burns and corrosions (T20-T32) (via L58.-), X32 — Exposure to sunlight (via L58.-).

These codes’ tabular lists name this diagnosis as distinct — both may be reported when both are documented.

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):SKN005 — Contact dermatitis (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 (Contact dermatitis).

L24.B1 — Irritant contact dermatitis related to digestive stoma or fistula, L24.B2 — Irritant contact dermatitis related to respiratory stoma or fistula, L24.B3 — Irritant contact dermatitis related to fecal or urinary stoma or fistula, L25.0 — Unspecified contact dermatitis due to cosmetics, L25.1 — Unspecified contact dermatitis due to drugs in contact with skin, L25.2 — Unspecified contact dermatitis due to dyes, L25.3 — Unspecified contact dermatitis due to other chemical products, L25.4 — Unspecified contact dermatitis due to food in contact with skin, L25.5 — Unspecified contact dermatitis due to plants, except food, L25.8 — Unspecified contact dermatitis due to other agents, L25.9 — Unspecified contact dermatitis, unspecified cause, L56.8 — Other specified acute skin changes due to ultraviolet radiation, L56.9 — Acute skin change due to ultraviolet radiation, unspecified, L57.8 — Other skin changes due to chronic exposure to nonionizing radiation, L57.9 — Skin changes due to chronic exposure to nonionizing radiation, unspecified, L58.0 — Acute radiodermatitis, L58.1 — Chronic radiodermatitis, L59.0 — Erythema ab igne [dermatitis ab igne], L59.8 — Other specified disorders of the skin and subcutaneous tissue related to radiation, L59.9 — Disorder of the skin and subcutaneous tissue related to radiation, unspecified, +28 more

Same Index main term, other category

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

L30.0 — Nummular dermatitis (nummular), L30.1 — Dyshidrosis [pompholyx] (dyshydrotic), L30.3 — Infective dermatitis (infective), L30.4 — Erythema intertrigo (friction), L30.8 — Other specified dermatitis (hiemalis), L30.9 — Dermatitis, unspecified, L40.2 — Acrodermatitis continua (repens), L52 — Erythema nodosum (contusiformis), L56.2 — Photocontact dermatitis [berloque dermatitis] (photocontact), L56.8 — Other specified acute skin changes due to ultraviolet radiation (ultraviolet, acute), L57.8 — Other skin changes due to chronic exposure to nonionizing radiation (solare), L59.0 — Erythema ab igne [dermatitis ab igne] (heat), L59.8 — Other specified disorders of the skin and subcutaneous tissue related to radiation (due to, radiation), L71.0 — Perioral dermatitis (perioral), L73.0 — Acne keloid (papillaris capillitii), L81.7 — Pigmented purpuric dermatosis (Schamberg's), L85.3 — Xerosis cutis (dry skin), L98.1 — Factitial dermatitis (artefacta), N94.6 — Dysmenorrhea, unspecified (dysmenorrheica), T69.1 — Chilblains (congelationis), +94 more

Contextual Map

Every relationship of L58.9 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.

Run L58.9 with these 11 related codes in Claim Check

Hierarchy

Referenced by Excludes1 notes

  • K13.0 — Diseases of lips[Excludes1](via L58.-): “cheilitis due to radiation-related disorders (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • T66 — Radiation sickness, unspecified[Excludes1](via L58.-): “radiation related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • T67 — Effects of heat and light[Excludes1](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026

Referenced by Excludes2 notes (14)

  • L20 — Atopic dermatitis[Excludes2](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • L20-L30 — Dermatitis and eczema (L20-L30)[Excludes2](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • L21 — Seborrheic dermatitis[Excludes2](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • L22 — Diaper dermatitis[Excludes2](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • L23 — Allergic contact dermatitis[Excludes2](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • L24 — Irritant contact dermatitis[Excludes2](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • L25 — Unspecified contact dermatitis[Excludes2](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • L26 — Exfoliative dermatitis[Excludes2](via L58.-): “radiation-related disorders of the skin and subcutaneous tissue (L55-L59)”— CMS ICD-10-CM tabular instructional notes · icd10cm-fy2026
  • and 6 more

Clinical classification (CCSR)

MS-DRG Grouper

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

  • Dermatitis (eczematous), due to, radioactive substance[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Dermatitis (eczematous), due to, radium[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Dermatitis (eczematous), due to, X-rays[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026
  • Radiodermatitis[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes

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

Cite this page

Reference this page in a research guide, syllabus or article. The release is included because code content changes each year.

MedCoder.ai. "L58.9 — Radiodermatitis, unspecified." ICD-10-CM FY2026. https://medcoder.ai/icd10/code/l58.9-radiodermatitis-unspecified

Change history

  • FY2016 — October 1, 2015
    In the code set at ICD-10-CM adoption
    Radiodermatitis, unspecified

No changes since FY2016 — additions, deletions, description changes and billable-status changes are tracked through FY2027 (effective October 1, 2026), and none are recorded for this code. Note changes are tracked from FY2027 only.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to L58.9 in its code family, with their registry titles.

View all codes in the L58 family