L12.9 ICD-10-CM Code: Pemphigoid, unspecified

Coding instructions

Official Tabular Instructional Notes: the inclusion, exclusion and sequencing notes published for L12.9 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 L12.9 itself; “inherited from” names the category or block whose note applies here.

Coder workflow for L12.9

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

Before you code L12.9

1. Unspecified does not mean incorrect. When the record gives no greater specificity, L12.9 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).

   ReviewL12.0, L12.1, L12.2, L12.3, L12.8

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

2. Check the Excludes1 note: if the documentation supports a condition named there, do not simply proceed with L12.9. Excludes1 conditions are not reported together with this code unless the record shows they are unrelated (Guidelines I.A.12.a).

   See the official tabular notes

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 — L12.9 is appropriate when the documentation goes no further.

   ReviewL12.0, L12.1, L12.2, L12.3, L12.8

2. Does the documentation support a condition named in L12.9’s Excludes1 note?
   Yes → Do not simply proceed: review the excluded code. Both are reported only when the record shows the two conditions are unrelated.
   No → Continue.

   ReviewO26.4, L40.1, L00

Consider L12.9. 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

• Excludes1 — check before selecting L12.9(5 notes)

  Coding workflow: If the documentation supports a condition named in this note, do not simply proceed with L12.9: the two are not reported together. The one exception is when the record shows the two conditions are unrelated to each other.

  CompareO26.4, L40.1, L00

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

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 (1)

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.

• Pemphigoid

Don’t confuse L12.9 with…

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

The codes most likely to be picked instead of L12.9 — 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.

• O26.4— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of herpes gestationis moves the case to O26.4; the two are not reported together unless documented as unrelated.

  Full comparison: L12.9 vs O26.4 →

• L40.1— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of impetigo herpetiformis moves the case to L40.1; the two are not reported together unless documented as unrelated.

  Full comparison: L12.9 vs L40.1 →

• L00— Excludes1 conflict (Excludes1 — generally not reported together)

  Not coded here — the tabular list excludes this pair for the same encounter.

  Not reported together with this code, except where the two conditions are documented as unrelated.

  What moves you there: Documentation of staphylococcal scalded skin syndrome moves the case to L00; the two are not reported together unless documented as unrelated.

  Full comparison: L12.9 vs L00 →

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

• CC as a secondary diagnosis (FY2026). Can raise the stay's MS-DRG severity tier.

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: CC — Complication or Comorbidity. Reported as a secondary diagnosis, this code raises the stay's MS-DRG severity tier — except when the principal diagnosis is one of 21 clinically related codes on its CMS exclusion list.

Named in the grouper logic of 2 MS-DRGs: DRG 595 (MDC 09), DRG 596 (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):SKN002 — Other specified inflammatory condition of skin (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 process (MS-DRG)

Acts as CC — raises the severity of other admissions. CMS groups these diagnoses into one MS-DRG principal-diagnosis exclusion process — a CC/MCC on this list never raises severity when the principal diagnosis is also on it.

L10.0 — Pemphigus vulgaris, L10.1 — Pemphigus vegetans, L10.2 — Pemphigus foliaceous, L10.3 — Brazilian pemphigus [fogo selvagem], L10.4 — Pemphigus erythematosus, L10.5 — Drug-induced pemphigus, L10.81 — Paraneoplastic pemphigus, L10.89 — Other pemphigus, L10.9 — Pemphigus, unspecified, L12.0 — Bullous pemphigoid, L12.1 — Cicatricial pemphigoid, L12.8 — Other pemphigoid, L13.8 — Other specified bullous disorders, L13.9 — Bullous disorder, unspecified, L44.8 — Other specified papulosquamous disorders, L44.9 — Papulosquamous disorder, unspecified, L94.2 — Calcinosis cutis, L94.4 — Gottron's papules, L98.7 — Excessive and redundant skin and subcutaneous tissue, L98.8 — Other specified disorders of the skin and subcutaneous tissue

Same CMS-HCC risk category (V28)

CMS maps these diagnoses to the same Hierarchical Condition Category (Pemphigus, Pemphigoid, and Other Specified Autoimmune Skin Disorders) for risk-adjusted payment.

D86.3 — Sarcoidosis of skin, L10.0 — Pemphigus vulgaris, L10.1 — Pemphigus vegetans, L10.2 — Pemphigus foliaceous, L10.3 — Brazilian pemphigus [fogo selvagem], L10.4 — Pemphigus erythematosus, L10.81 — Paraneoplastic pemphigus, L10.89 — Other pemphigus, L10.9 — Pemphigus, unspecified, L12.0 — Bullous pemphigoid, L12.1 — Cicatricial pemphigoid, L12.8 — Other pemphigoid, L88 — Pyoderma gangrenosum

Same clinical category (CCSR)

AHRQ's Clinical Classifications Software groups these diagnoses under the same clinical category (Other specified inflammatory condition of skin).

L11.1 — Transient acantholytic dermatosis [Grover], L11.8 — Other specified acantholytic disorders, L11.9 — Acantholytic disorder, unspecified, L12.0 — Bullous pemphigoid, L12.1 — Cicatricial pemphigoid, L12.2 — Chronic bullous disease of childhood, L12.30 — Acquired epidermolysis bullosa, unspecified, L12.31 — Epidermolysis bullosa due to drug, L12.35 — Other acquired epidermolysis bullosa, L12.8 — Other pemphigoid, L13.0 — Dermatitis herpetiformis, L13.1 — Subcorneal pustular dermatitis, L13.8 — Other specified bullous disorders, L13.9 — Bullous disorder, unspecified, L14 — Bullous disorders in diseases classified elsewhere, L20.0 — Besnier's prurigo, L20.81 — Atopic neurodermatitis, L20.82 — Flexural eczema, L20.83 — Infantile (acute) (chronic) eczema, L20.84 — Intrinsic (allergic) eczema, +145 more

Contextual Map

Every relationship of L12.9 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

• L00-L99 — Chapter 12: Diseases of the Skin and Subcutaneous Tissue (L00-L99) (L00-L99)[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L10-L14 — Bullous disorders[Hierarchy]— CMS ICD-10-CM tabular structure · icd10cm-fy2026

Clinical classification (CCSR)

• SKN002 — Other specified inflammatory condition of skin[CCSR]— AHRQ CCSR for ICD-10-CM Diagnoses (HCUP)

Risk adjustment (CMS-HCC)

• HCC 387 — Pemphigus, Pemphigoid, and Other Specified Autoimmune Skin Disorders [CMS-HCC]— CMS-HCC V28 · 2026

MS-DRG Grouper

• CC — Complication or Comorbidity [MS-DRG severity]: “As a secondary diagnosis this code can raise the stay's MS-DRG severity tier (CC).”— CMS MS-DRG Definitions Manual (Appendix C) · FY2026
• DRG 595 — MAJOR SKIN DISORDERS WITH MCC[MS-DRG]: “MAJOR SKIN DISORDERS WITH MCC (MDC 09)”— CMS MS-DRG Definitions Manual (Appendix B) · FY2026
• DRG 596 — MAJOR SKIN DISORDERS WITHOUT MCC[MS-DRG]: “MAJOR 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

• Pemphigoid[Index term]— CMS ICD-10-CM Index to Diseases and Injuries · icd10cm-fy2026

Nearest codes (9)

• L12 — Pemphigoid[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L12.0 — Bullous pemphigoid[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L12.1 — Cicatricial pemphigoid[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L12.2 — Chronic bullous disease of childhood[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L12.3 — Acquired epidermolysis bullosa[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L12.30 — Acquired epidermolysis bullosa, unspecified[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L12.31 — Epidermolysis bullosa due to drug[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• L12.35 — Other acquired epidermolysis bullosa[Sibling]— CMS ICD-10-CM tabular structure · icd10cm-fy2026
• and 1 more

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

Risk adjustment Official source data

2026 Mid-Year Final ICD-10 Mappings + Model Software (cms.gov/files/zip/2026-midyear-final-icd-10-mappings.zip, 2026-midyear-final-model-software.zip) — CMS-HCC V28, PY2026 mid-year final release 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 L12.9 in its code family, with their registry titles.

• L12 — Pemphigoid
• L12.0 — Bullous pemphigoid
• L12.1 — Cicatricial pemphigoid
• L12.2 — Chronic bullous disease of childhood
• L12.3 — Acquired epidermolysis bullosa
• L12.30 — Acquired epidermolysis bullosa, unspecified
• L12.31 — Epidermolysis bullosa due to drug
• L12.35 — Other acquired epidermolysis bullosa
• L12.8 — Other pemphigoid

View all codes in the L12 family