T20.4 — Corrosion of unspecified degree of head, face, and neck
Is T20.4 billable?
No — T20.4 is a non-billable header code. T20.4 groups more specific codes and cannot be submitted on a claim. A valid ICD-10-CM code must be reported at the highest level of specificity available in its branch. Select one of the 33 billable codes beneath T20.4.
Billable codes under this header
- T20.40XACorrosion of unspecified degree of head, face, and neck, unspecified site, initial encounter
- T20.40XDCorrosion of unspecified degree of head, face, and neck, unspecified site, subsequent encounter
- T20.40XSCorrosion of unspecified degree of head, face, and neck, unspecified site, sequela
- T20.42XACorrosion of unspecified degree of lip(s), initial encounter
- T20.42XDCorrosion of unspecified degree of lip(s), subsequent encounter
- T20.42XSCorrosion of unspecified degree of lip(s), sequela
- T20.43XACorrosion of unspecified degree of chin, initial encounter
- T20.43XDCorrosion of unspecified degree of chin, subsequent encounter
- T20.43XSCorrosion of unspecified degree of chin, sequela
- T20.44XACorrosion of unspecified degree of nose (septum), initial encounter
- T20.44XDCorrosion of unspecified degree of nose (septum), subsequent encounter
- T20.44XSCorrosion of unspecified degree of nose (septum), sequela
- T20.45XACorrosion of unspecified degree of scalp [any part], initial encounter
- T20.45XDCorrosion of unspecified degree of scalp [any part], subsequent encounter
- T20.45XSCorrosion of unspecified degree of scalp [any part], sequela
- T20.46XACorrosion of unspecified degree of forehead and cheek, initial encounter
- T20.46XDCorrosion of unspecified degree of forehead and cheek, subsequent encounter
- T20.46XSCorrosion of unspecified degree of forehead and cheek, sequela
- T20.47XACorrosion of unspecified degree of neck, initial encounter
- T20.47XDCorrosion of unspecified degree of neck, subsequent encounter
- T20.47XSCorrosion of unspecified degree of neck, sequela
- T20.49XACorrosion of unspecified degree of multiple sites of head, face, and neck, initial encounter
- T20.49XDCorrosion of unspecified degree of multiple sites of head, face, and neck, subsequent encounter
- T20.49XSCorrosion of unspecified degree of multiple sites of head, face, and neck, sequela
- T20.411ACorrosion of unspecified degree of right ear [any part, except ear drum], initial encounter
- T20.411DCorrosion of unspecified degree of right ear [any part, except ear drum], subsequent encounter
- T20.411SCorrosion of unspecified degree of right ear [any part, except ear drum], sequela
- T20.412ACorrosion of unspecified degree of left ear [any part, except ear drum], initial encounter
- T20.412DCorrosion of unspecified degree of left ear [any part, except ear drum], subsequent encounter
- T20.412SCorrosion of unspecified degree of left ear [any part, except ear drum], sequela
- T20.419ACorrosion of unspecified degree of unspecified ear [any part, except ear drum], initial encounter
- T20.419DCorrosion of unspecified degree of unspecified ear [any part, except ear drum], subsequent encounter
- T20.419SCorrosion of unspecified degree of unspecified ear [any part, except ear drum], sequela
T20.4 at a glance
| Code | T20.4 |
|---|---|
| Description | Corrosion of unspecified degree of head, face, and neck |
| Billable | No — header code |
| Code set | ICD-10-CM FY2027 |
| Valid for encounters | October 1, 2026 – September 30, 2027 |
Code first
The underlying condition below must be sequenced before T20.4. T20.4 describes a manifestation and cannot be the principal or first-listed diagnosis.
- (T51-T65) to identify chemical and intent
Use additional code
Report an additional code alongside T20.4 to fully describe the condition. T20.4 is sequenced first.
- external cause code to identify place (Y92)
Use additional code — inherited from Chapter 19
Report an additional code alongside T20.4 to fully describe the condition. T20.4 is sequenced first.
- code to identify any retained foreign body, if applicable (Z18.-)
Use additional code — inherited from T20-T25
Report an additional code alongside T20.4 to fully describe the condition. T20.4 is sequenced first.
Excludes2 — not included here — inherited from Chapter 19
The conditions below are not part of T20.4, but a patient may have both at the same time. When documentation supports it, T20.4 and the excluded code may both be reported.
Excludes2 — not included here — inherited from T20
The conditions below are not part of T20.4, but a patient may have both at the same time. When documentation supports it, T20.4 and the excluded code may both be reported.
What codes fall under T20.4? (9)
- T20.40Corrosion of unspecified degree of head, face, and neck, unspecified sitenot billable
- T20.41Corrosion of unspecified degree of ear [any part, except ear drum]not billable
- T20.42Corrosion of unspecified degree of lip(s)not billable
- T20.43Corrosion of unspecified degree of chinnot billable
- T20.44Corrosion of unspecified degree of nose (septum)not billable
- T20.45Corrosion of unspecified degree of scalp [any part]not billable
- T20.46Corrosion of unspecified degree of forehead and cheeknot billable
- T20.47Corrosion of unspecified degree of necknot billable
- T20.49Corrosion of unspecified degree of multiple sites of head, face, and necknot billable
How long has T20.4 existed?
T20.4 has been in ICD-10-CM since at least FY2016, the earliest fiscal year on record here.
Derived from the official order files for FY2016–FY2026. FY2017 and FY2020 publish no order file, so those years are not covered.
What other codes are in the T20 family? (7)
- T20.0Burn of unspecified degree of head, face, and necknot billable
- T20.1Burn of first degree of head, face, and necknot billable
- T20.2Burn of second degree of head, face, and necknot billable
- T20.3Burn of third degree of head, face, and necknot billable
- T20.5Corrosion of first degree of head, face, and necknot billable
- T20.6Corrosion of second degree of head, face, and necknot billable
- T20.7Corrosion of third degree of head, face, and necknot billable