2027 ICD-10-CM Diagnosis Code B02.0Zoster encephalitis
ICD-10-CM Codes›A00–B99›B00-B09›B02
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Not Chronic
B02.0 is a billable ICD-10-CM diagnosis code for zoster encephalitis. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 73 through 74, 791, 793, 974 through 976. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 34 closely related codes. Coders also document this condition as herpes zoster encephalitis. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Encephalitis and Viral infection.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Herpes zoster encephalitis
- Post-infectious encephalitis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to B02.0: its own notes plus those printed at B02 and Chapter 1. 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.
- shingles
- zona
- diseases generally recognized as communicable or transmissible
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Zoster meningoencephalitis
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.
- carrier or suspected carrier of infectious disease (Z22.-)
- certain localized infections - see body system-related chapters
- infectious and parasitic diseases complicating pregnancy, childbirth and the puerperium (O98.-)
- infectious and parasitic diseases specific to the perinatal period (P35-P39)
- influenza and other acute respiratory infections (J00-J22)
Use Additional Code
Add a second code, after this one, to fully describe the condition.
- code to identify resistance to antimicrobial drugs (Z16.-)
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name B02.0, its category, or a range that includes it.
Excludes1 2
These codes carry an Excludes1 note naming B02.0: they are not reported together with it, unless the two conditions are unrelated.
Excludes2 4
These codes carry an Excludes2 note naming B02.0: its condition is not part of those codes, and both may be reported when the patient has both.
- B10 Other human herpesvirusesherpes zoster (B02.-) names B02.-, which includes this code
- B10 Other human herpesviruseshuman herpesvirus 3 (B01.-, B02.-) names B02.-, which includes this code
- B10 Other human herpesviruseszoster (B02.-) names B02.-, which includes this code
- Block L00-L08 Infections of the skin and subcutaneous tissuezoster (B02.-) names B02.-, which includes this code
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
Encephalitis (chronic) (hemorrhagic) (idiopathic) (nonepidemic) (spurious) (subacute) G04.90
herpes zoster B02.0
zoster B02.0
Herpes, herpesvirus, herpetic B00.9
zoster See Also: condition; B02.9
encephalitis B02.0
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Patient EducationClinical
Encephalitis
Encephalitis is inflammation (swelling) of the brain. It can happen when an infection or medical condition that affects the brain activates your immune system. The inflammation can cause a wide range of symptoms. In extreme cases, it can lead to brain damage, stroke, or even death.
The full article covers:
- What is encephalitis?
- What causes encephalitis?
- Who is more likely to get encephalitis?
- What are the symptoms of encephalitis?
- How is encephalitis diagnosed?
- What are the treatments for encephalitis?
- Can encephalitis be prevented?
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert B02.0 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About B02.0Overview
What is the ICD-10 code for zoster encephalitis?
The ICD-10-CM code for zoster encephalitis is B02.0 (sometimes written as B020). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is B02.0 (Zoster [herpes zoster]) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report zoster encephalitis on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does B02.0 group to?
When zoster encephalitis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 793, 791, 974, 74, 976, 73, 975, with relative weights from 0.7879 to 4.2192 depending on complications. Higher weights mean higher Medicare reimbursement.
Is B02.0 a CC or MCC?
CMS lists B02.0 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 34 closely related codes in its exclusion list.
What is the ICD-9 equivalent of B02.0?
Under the General Equivalence Mappings, zoster encephalitis converts to ICD-9-CM 053.19 (h zoster nerv syst NEC). The mapping is approximate, so confirm the match fits the documentation.
