ICD-10-CM 2027 diagnosis code
T22.549ACorrosion of first degree of unspecified axilla, initial encounter
T22.549A is a valid, billable ICD-10-CM code for corrosion of first degree of unspecified axilla, initial encounter. It can be reported on claims for dates of service from October 1, 2026 – September 30, 2027.Short description: Corrosion of first degree of unspecified axilla, init encntr
Code unchanged since ICD-10-CM took effect on October 1, 2015. Source: official FY2027 ICD-10-CM release from CDC/NCHS and CMS. Page updated September 29, 2026. About our data
About T22.549A
T22.549A is the ICD-10-CM diagnosis code for corrosion of first degree of unspecified axilla, initial encounter. It belongs to category T22 (burn and corrosion of shoulder and upper limb, except wrist and hand), block T20-T25 (burns and corrosions of external body surface, specified by site) and chapter 19 (injury, poisoning and certain other consequences of external causes). It is billable, so it can be reported on its own for dates of service from October 1, 2026 through September 30, 2027.
The 7th character "A" means initial encounter: use it while the patient is receiving active treatment for the condition.
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 935 (Non-Extensive Burns, relative weight 2.4243), in MDC 22 (Burns), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
It has been part of ICD-10-CM since the code set took effect on October 1, 2015 and hasn't changed since.
Before ICD-10, this condition was coded in ICD-9-CM as 943.14 (erythema [first degree] of axilla).
7th character
Ainitial encounter
Other encounter types for T22.549:
Notes that apply from higher levels
Instructions written at a parent level also apply to T22.549A.
Broader instructions also apply from T20-T25 Burns and corrosions of external body surface, specified by site and Chapter 19: Injury, poisoning and certain other consequences of external causes.
MS-DRG v44.0 grouping
All DRGs →Inpatient MS-DRGs this diagnosis can group to, as the principal or a secondary diagnosis, depending on the rest of the claim.
MDC 22 · Burns
ICD-9-CM equivalent
Converter →- 943.14Erythema [first degree] of axillaapproximate
From the CMS 2018 General Equivalence Mappings (GEMs), the final GEMs release.
Code history
- 2016
- 2017
- 2018
- 2019
- 2020
- 2021
- 2022
- 2023
- 2024
- 2025
- 2026
- 2027
- FY2016 (effective 10/1/2015): Added (first year of ICD-10-CM)
- No changes since FY2016.
Common questions about T22.549A
Is T22.549A billable?
- Yes. T22.549A is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
What does the "A" at the end of T22.549A mean?
- It is the 7th character for initial encounter. Per the official guidelines, use it while the patient is receiving active treatment for the condition.
Can T22.549A be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict T22.549A as a principal diagnosis.
Is T22.549A a CC or MCC?
- No. T22.549A is neither a CC nor an MCC under MS-DRG v44.0.
What DRG does T22.549A group to?
- T22.549A is used in the MS-DRG v44.0 logic for MS-DRG 935 (Non-Extensive Burns). Which one applies depends on whether it is the principal diagnosis and on the rest of the claim.
What is the ICD-9 code for T22.549A?
- The CMS General Equivalence Mappings map T22.549A to ICD-9-CM 943.14.