2027 ICD-10-CM Diagnosis Code S01.359AOpen bite of unspecified ear, initial encounter

ICD-10-CM Codes›S00–T88›S00-S09›S01

ICD-10-CM S01.359A
CMSSource: CMS FY 2027 ICD-10-CM dataset · Effective Oct 1, 2026 – Sep 30, 2027

S01.359A is a billable ICD-10-CM diagnosis code for open bite of unspecified ear, initial encounter. The 7th character A marks it as an initial encounter code, used while the patient is receiving active treatment. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 154 through 156, 963 through 965. Coders also document this condition as animal bite of ear region. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Open wounds of head and neck, initial encounter.

Code Identity

ICD-10-CM Code
S01.359A
Billable Status
Yes — Valid for Submission
Code Describes
Open bite of unspecified ear, initial encounter
Short Description
Open bite of unspecified ear, initial encounter
Same as the full description in the CMS dataset.
Parent Code
S01.359
Open bite of unspecified ear

Code Classification

ChapterS00–T88Injury, poisoning and certain other consequences of external causes
SectionS00-S09Injuries to the head
CategoryS01Open wound of head
This CodeS01.359AOpen bite of unspecified ear, initial encounter

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Animal bite of ear region
  • Bite wound of external ear
  • Dog bite of ear region
  • Human bite of ear region
  • Open wound of ear due to animal bite
  • Open wound of ear due to bite
  • Open wound of ear due to cat bite
  • Open wound of ear due to human bite

Coding GuidelinesGuidance

The appropriate 7th character is to be added to each code from block Open wound of head (S01). Use the following options for the applicable episode of care:

  • A - initial encounter
  • D - subsequent encounter
  • S - sequela

Source: ICD-10-CM Official Guidelines for Coding and Reporting, FY 2027, published by CMS and the National Center for Health Statistics.

Instructional NotesGuidance

Instructions from the official ICD-10-CM Tabular List that apply to S01.359A: its own notes plus those printed at S01.35, S01, block S00-S09, and Chapter 19. A note printed at a category, block or chapter applies to every code under it.

Includes

Further defines, or gives examples of, the content of the category.

From Block S00-S09 Injuries to the head applies to 1,934 codes
  • injuries of ear
  • injuries of eye
  • injuries of face [any part]
  • injuries of gum
  • injuries of jaw
  • injuries of oral cavity
  • injuries of palate
  • injuries of periocular area
  • injuries of scalp
  • injuries of temporomandibular joint area
  • injuries of tongue
  • injuries of tooth

Excludes1

Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.

From S01.35 Open bite of ear applies to 9 codes
From S01 Open wound of head applies to 270 codes
  • open skull fracture (S02.- with 7th character B)

Excludes2

Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.

From S01 Open wound of head applies to 270 codes
  • injury of eye and orbit (S05.-)
  • traumatic amputation of part of head (S08.-)
From Block S00-S09 Injuries to the head applies to 1,934 codes
  • burns and corrosions (T20-T32)
  • effects of foreign body in ear (T16)
  • effects of foreign body in larynx (T17.3)
  • effects of foreign body in mouth NOS (T18.0)
  • effects of foreign body in nose (T17.0-T17.1)
  • effects of foreign body in pharynx (T17.2)
  • effects of foreign body on external eye (T15.-)
  • frostbite (T33-T34)
  • insect bite or sting, venomous (T63.4)
From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes

Use Additional Code

Add a second code, after this one, to fully describe the condition.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • code to identify any retained foreign body, if applicable (Z18.-)

Code Also

A second code may be needed to fully describe the condition; the note gives no sequencing direction.

From S01 Open wound of head applies to 270 codes
  • any associated:
  • injury of cranial nerve (S04.-)
  • injury of muscle and tendon of head (S09.1-)
  • intracranial injury (S06.-)
  • wound infection
From Block S00-S09 Injuries to the head applies to 1,934 codes
  • for any associated infection

Notes

General instructions on how these codes are used.

From Chapter 19 (S00-T88) Injury, poisoning and certain other consequences of external causes applies to 41,187 codes
  • 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.

7th Character

Every code in the category takes a 7th character from the listed values, with the placeholder X filling any empty positions before it.

From S01 Open wound of head applies to 270 codes
  • The appropriate 7th character is to be added to each code from category S01
Values for category S01 Encounter: Initial, Subsequent, Sequela
  • Ainitial encounter this code
  • Dsubsequent encounter
  • Ssequela

Source: CMS ICD-10-CM Tabular List. How to read instructional notes.

Referenced in Other NotesGuidance

Instructional notes printed at other codes that name S01.359A, its category, or a range that includes it.

Excludes1 2

These codes carry an Excludes1 note naming S01.359A: they are not reported together with it, unless the two conditions are unrelated.

  • S00 Superficial injury of head
    open wound of head (S01.-) names S01.-, which includes this code
  • S00.47 Other superficial bite of ear
    open bite of ear (S01.35) names S01.35, which includes this code

Excludes2 1

These codes carry an Excludes2 note naming S01.359A: its condition is not part of those codes, and both may be reported when the patient has both.

  • S09.3 Other specified and unspecified injury of middle and inner ear
    injury to external ear (S00.4-, S01.3-, S08.1-) names S01.3-, which includes this code

Code Also 3

These codes say S01.359A may also be needed to fully describe the condition. The note gives no sequencing direction.

  • S04 Injury of cranial nerve
    open wound of head (S01.-) names S01.-, which includes this code
  • S06 Intracranial injury
    open wound of head (S01.-) names S01.-, which includes this code
  • S09.1 Injury of muscle and tendon of head
    any associated open wound (S01.-) names S01.-, which includes this code

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR INJ011
Open wounds of head and neck, initial encounter
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Animal Bites

Wild animals usually avoid people. They might attack, however, if they feel threatened, are sick, or are protecting their young or territory. Attacks by pets are more common. Animal bites rarely are life-threatening, but if they become infected, you can develop serious medical problems.

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert S01.359A to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
872.01 Open wound of auricle
Approximate The match is approximate rather than exact.
ICD-9-CM
872.02 Opn wound auditory canal
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2026No changes
FY 2027CurrentCurrent code set, no changesEffective October 1, 2026 through September 30, 2027.

Questions About S01.359AOverview

What is the ICD-10 code for open bite of unspecified ear, initial encounter?

The ICD-10-CM code for open bite of unspecified ear, initial encounter is S01.359A (sometimes written as S01359A). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

Is S01.359A (Open bite of unspecified ear) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report open bite of unspecified ear, initial encounter on HIPAA-covered claims from October 1, 2026 through September 30, 2027.

What does the 7th character A in S01.359A mean?

The final character A marks the initial encounter: use it while the patient is receiving active treatment for open bite of unspecified ear, such as an emergency visit or first evaluation.

What MS-DRG does S01.359A group to?

When open bite of unspecified ear, initial encounter is the principal diagnosis on an inpatient stay, it groups to MS-DRG 156, 964, 965, 155, 154, 963, with relative weights from 0.6656 to 2.6361 depending on complications. Higher weights mean higher Medicare reimbursement.

Can S01.359A be reported with S00.46?

Not as a rule. The Excludes1 note at S01.35, which applies to S01.359A, lists "superficial bite of ear (S00.46, S00.47)". An Excludes1 note means the excluded code is never reported together with this one; the only exception is when the two conditions are unrelated to each other (Official Guidelines, Section I.A.12.a).