T20.4
Corrosion of unspecified degree of head, face, and neck
Not billable — category only FY2026 2025-10-01 → 2026-09-30
This is the unspecified option. 7 more
specific codes sit alongside it. Worth
checking whether the documentation supports one of them.
Exclusions 5 never code together
T20code
Excludes2 — not included here, but the patient may have both. Code both when documented.
7th character 3
A initial encounter
D subsequent encounter
S sequela
Instructional notes 5
T20.4code
S00-T88chapter
Notes
- Use secondary code(s) from Chapter 20, External causes of morbidity, to indicate cause of injury. Codes within the T section that include the external cause do not require an additional external cause code
- The chapter uses the S-section for coding different types of injuries related to single body regions and the T-section to cover injuries to unspecified body regions as well as poisoning and certain other consequences of external causes.
Use additional code
- code to identify any retained foreign body, if applicable (Z18.-)Z18.-
Index entries leading here filed at null
No alphabetic index entry points at this code.
Alongside this code 7 same parent — T20
T20.0 Burn of unspecified degree of head, face, and neck category T20.1 Burn of first degree of head, face, and neck category T20.2 Burn of second degree of head, face, and neck category T20.3 Burn of third degree of head, face, and neck category T20.5 Corrosion of first degree of head, face, and neck category T20.6 Corrosion of second degree of head, face, and neck category T20.7 Corrosion of third degree of head, face, and neck category
Subordinate codes 9
T20.40 Corrosion of unsp degree of head, face, and neck, unsp site T20.41 Corrosion of unspecified degree of ear T20.42 Corrosion of unspecified degree of lip(s) T20.43 Corrosion of unspecified degree of chin T20.44 Corrosion of unspecified degree of nose (septum) T20.45 Corrosion of unspecified degree of scalp [any part] T20.46 Corrosion of unspecified degree of forehead and cheek T20.47 Corrosion of unspecified degree of neck T20.49 Corrosion of unsp deg mult sites of head, face, and neck
Medications 1
MED-RT files conditions by MeSH, which carves the world differently from ICD-10. These are name matches on this code's description, offered as candidates — not as an assertion that they are this code.
Additional references
AHA Coding Clinic® Licence required
Official coding advice for this code. Published by the American Hospital Association. Not included in this installation.