T20.419D
Corrosion of unspecified degree of unspecified ear [any part, except ear drum], subsequent encounter
T20.419D (also written T20419D) is a billable ICD-10-CM diagnosis code for corrosion of unspecified degree of unspecified ear [any part, except ear drum], subsequent encounter. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 264 codes in category T20 (Burn and corrosion of head, face, and neck). Its 7th character, D, means subsequent encounter. Its coding notes include a Code first instruction, a Use additional code instruction and 6 Excludes2 entries.
7th character
Category T20 requires a 7th character.
Guidelines tips
From the FY2027 Official Guidelines. ICD10Ref adds no rules of its own.
The 7th character depends on whether the patient is in active treatment, not on who sees the patient. An aftercare Z code is not used for injury aftercare.
Burns are classified by depth, extent and agent. Burns of the same site and side but different degrees take the highest degree. Non-healing burns are coded as acute burns.
Late effects of burns are coded with 7th character S, and a current burn and a sequela of an old burn can be coded together. An external cause code is used with burns.
Code first
If the underlying condition listed here is present and known, sequence it first.
Use additional code
Add the listed code as a secondary code, if known.
- external cause code to identify place (Y92)
Also from chapter/block level (2 notes)
- code to identify any retained foreign body, if applicable (Z18.-)
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
- corrosion of ear drum (T28.91-)
Also from chapter/block level (2 notes)
- birth trauma (P10-P15)
- obstetric trauma (O70-O71)
Includes
Further defines or gives examples of the content of the category.
Also from chapter/block level (3 notes)
- 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]
Notes
Also from chapter/block level (2 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.