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T20.66XA ICD-10-CM Code: Corrosion of second degree of forehead and cheek, initial encounter

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

Inpatient Payment Groups (MS-DRG)

MS-DRGs this diagnosis helps define, as principal or secondary, per the CMS ICD-10-CM/PCS MS-DRG Definitions Manual v43.0, Appendix B.

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.

Official Registry Overview & Definition

Corrosion of second degree of forehead and cheek, initial encounter is a billable ICD-10-CM diagnosis code (T20.66A).

Official Tabular Instructional Notes

Sequencing, inclusion, and exclusion notes published for T20.66XA in the official ICD-10-CM tabular list.

Includes

Conditions the official ICD-10-CM tabular list includes under this code.

  • burns and corrosions of first degree [erythema]
  • burns and corrosions of second degree [blisters][epidermal loss]
  • burns and corrosions of third degree [deep necrosis of underlying tissue] [full- thickness skin loss]

Excludes2 — Not Included Here

Conditions not covered by this code, but which may be reported alongside it when both are present.

Code First

Underlying conditions that must be sequenced before this code.

  • (T51-T65) to identify chemical and intent

Use Additional Code

Supplementary codes the tabular list directs you to add.

  • external cause code to identify place (Y92)
  • Use additional code from category T31 or T32 to identify extent of body surface involved

Frequently Compared Codes

The official Excludes notes on T20.66XA name these codes. Each comparison page covers when the two can — or must not — be reported together.

Change history

No changes recorded for this code — unchanged since the FY2016 baseline of the change ledger.

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.

Contextual Map

Every relationship of T20.66XA 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

  • S00-T88 — Chapter 19: Injury, Poisoning and Certain Other Consequences of External Causes (S00-T88) (S00-T88) [Hierarchy]
  • T20-T25 — Burns and corrosions of external body surface, specified by site [Hierarchy]

Referenced by Excludes1 notes

  • T07 — Unspecified multiple injuries [Excludes1](via T20.-): “burns and corrosions (T20-T32)” · check together
  • T66 — Radiation sickness, unspecified [Excludes1](via T20.-): “burns (T20-T31)” · check together

Referenced by Excludes2 notes (121)

  • S00 — Superficial injury of head [Excludes2](via T20.-): “burns and corrosions (T20-T32)” · check together
  • S00-S09 — Injuries to the head (S00-S09) [Excludes2](via T20.-): “burns and corrosions (T20-T32)” · check together
  • S01 — Open wound of head [Excludes2](via T20.-): “burns and corrosions (T20-T32)” · check together
  • S02 — Fracture of skull and facial bones [Excludes2](via T20.-): “burns and corrosions (T20-T32)” · check together
  • S03 — Dislocation and sprain of joints and ligaments of head [Excludes2](via T20.-): “burns and corrosions (T20-T32)” · check together
  • S04 — Injury of cranial nerve [Excludes2](via T20.-): “burns and corrosions (T20-T32)” · check together
  • S05 — Injury of eye and orbit [Excludes2](via T20.-): “burns and corrosions (T20-T32)” · check together
  • S06 — Intracranial injury [Excludes2](via T20.-): “burns and corrosions (T20-T32)” · check together
  • and 113 more

Clinical classification (CCSR)

  • INJ019 — Burn and corrosion, initial encounter [CCSR]

Potential MS-DRG

  • DRG 935 — NON-EXTENSIVE BURNS [MS-DRG]: “NON-EXTENSIVE BURNS (MDC 22)”

MDC crossing · procedures (377)

  • MDC 22 — Burns [MDC crossing]: “Burns — 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.”
  • 0HR0X72 — Replacement of Scalp Skin with Autologous Tissue Substitute, Cell Suspension Technique, External Approach [Same-MDC procedure]: “Replacement of Scalp Skin with Autologous Tissue Substitute, Cell Suspension Technique, External Approach — grouped in MDC 22, the procedure side of this code's crossing.” · check together
  • 0HR0X73 — Replacement of Scalp Skin with Autologous Tissue Substitute, Full Thickness, External Approach [Same-MDC procedure]: “Replacement of Scalp Skin with Autologous Tissue Substitute, Full Thickness, External Approach — grouped in MDC 22, the procedure side of this code's crossing.” · check together
  • 0HR0X74 — Replacement of Scalp Skin with Autologous Tissue Substitute, Partial Thickness, External Approach [Same-MDC procedure]: “Replacement of Scalp Skin with Autologous Tissue Substitute, Partial Thickness, External Approach — grouped in MDC 22, the procedure side of this code's crossing.” · check together
  • 0HR0XJ3 — Replacement of Scalp Skin with Synthetic Substitute, Full Thickness, External Approach [Same-MDC procedure]: “Replacement of Scalp Skin with Synthetic Substitute, Full Thickness, External Approach — grouped in MDC 22, the procedure side of this code's crossing.” · check together
  • 0HR0XJ4 — Replacement of Scalp Skin with Synthetic Substitute, Partial Thickness, External Approach [Same-MDC procedure]: “Replacement of Scalp Skin with Synthetic Substitute, Partial Thickness, External Approach — grouped in MDC 22, the procedure side of this code's crossing.” · check together
  • and 372 more

Nearest codes (40)

  • T20 — Burn and corrosion of head, face, and neck [Sibling]
  • T20.619A — Corrosion of second degree of unspecified ear [any part, except ear drum], initial encounter [Sibling]
  • T20.619D — Corrosion of second degree of unspecified ear [any part, except ear drum], subsequent encounter [Sibling]
  • T20.619S — Corrosion of second degree of unspecified ear [any part, except ear drum], sequela [Sibling]
  • T20.62 — Corrosion of second degree of lip(s) [Sibling]
  • T20.62XA — Corrosion of second degree of lip(s), initial encounter [Sibling]
  • T20.62XD — Corrosion of second degree of lip(s), subsequent encounter [Sibling]
  • T20.62XS — Corrosion of second degree of lip(s), sequela [Sibling]
  • and 32 more

Referenced by Other Codes

Clinical classification (AHRQ CCSR):INJ019 — Burn and corrosion, initial encounter (default).

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

Potential MS-DRG Relationships (FY2026)

Not on the CMS CC/MCC list — as a secondary diagnosis this code does not change MS-DRG severity.

Named in the grouper logic of 1 MS-DRG: DRG 935 (MDC 22).

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

Official ICD-10-CM tabular notes on other codes that name T20.66XA or its code family.

2 Excludes1 notes: T07 (via T20.-), T66 (via T20.-).

121 Excludes2 notes: S00 (via T20.-), S00-S09 (via T20.-), S01 (via T20.-), S02 (via T20.-), S03 (via T20.-), S04 (via T20.-), S05 (via T20.-), S06 (via T20.-), S07 (via T20.-), S08 (via T20.-) and 111 more.

Frequently Asked Questions (FAQ) & Clinical Guidance

Does T20.66XA require a 7th character?

Yes. The appropriate 7th character is to be added to each code from category T20.

Nearest Codes in This Family

Official ICD-10-CM classifications closest to T20.66XA in its code family, with their registry titles.

  • T20.65 — Corrosion of second degree of scalp [any part]
  • T20.65XA — Corrosion of second degree of scalp [any part], initial encounter
  • T20.65XD — Corrosion of second degree of scalp [any part], subsequent encounter
  • T20.65XS — Corrosion of second degree of scalp [any part], sequela
  • T20.66 — Corrosion of second degree of forehead and cheek
  • T20.66XD — Corrosion of second degree of forehead and cheek, subsequent encounter
  • T20.66XS — Corrosion of second degree of forehead and cheek, sequela
  • T20.67 — Corrosion of second degree of neck
  • T20.67XA — Corrosion of second degree of neck, initial encounter
  • T20.67XD — Corrosion of second degree of neck, subsequent encounter

View all codes in the T20 family