ICD-10-CM 2027
ICD-10 code for Roseola
Unspecified viral infection characterized by skin and mucous membrane lesions
From the official ICD-10-CM alphabetic index entry “Roseola”. Page updated September 29, 2026.
About coding Roseola
The ICD-10-CM code for Roseola is B09 (Unspecified viral infection characterized by skin and mucous membrane lesions). The official index lists 3 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on B09.
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 865 (Viral Illness with MCC, relative weight 1.3485) and DRG 866 (Viral Illness without MCC, relative weight 0.8692), in MDC 18 (Infectious and Parasitic Diseases, Systemic or Unspecified Sites), 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.
More specific Roseola codes (official index)
Common questions about Roseola ICD-10 codes
What is the ICD-10 code for Roseola?
- B09 — Unspecified viral infection characterized by skin and mucous membrane lesions. More specific codes apply when the documentation supports them: B08.20, B08.21, B08.22.
What is the ICD-10 code for infantum roseola?
- B08.20 — Exanthema subitum [sixth disease], unspecified.
Is B09 billable?
- Yes. B09 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can B09 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict B09 as a principal diagnosis.
Is B09 a CC or MCC?
- No. B09 is neither a CC nor an MCC under MS-DRG v44.0.