2026 ICD-10-CM Diagnosis Code B85.3Phthiriasis

ICD-10-CM Codes›A00–B99›B85-B89›B85

ICD-10-CM B85.3
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

B85.3 is a billable ICD-10-CM diagnosis code for phthiriasis. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 606 through 607. Coders also document this condition as dermatosis caused by lice. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Parasitic, other specified and unspecified infections.

Code Identity

ICD-10-CM Code
B85.3
Billable Status
Yes — Valid for Submission
Code Describes
Phthiriasis
Short Description
Phthiriasis
Same as the full description in the CMS dataset.
Parent Code
B85
Pediculosis and phthiriasis

Code Classification

ChapterA00–B99Certain infectious and parasitic diseases
SectionB85-B89Pediculosis, acariasis and other infestations
CategoryB85Pediculosis and phthiriasis
This CodeB85.3Phthiriasis

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Dermatosis caused by lice
  • Disseminated phthiriasis
  • Infestation by Phthirus
  • Infestation by Phthirus pubis
  • Phthiriasis of eyelashes

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • Infestation by crab-louse
  • Infestation by Phthirus pubis

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • Crabs, meaning pubic lice
    • Infestation
      • crab-lice
    • Infestation
      • eyelid
        • in (due to)
          • phthiriasis
    • Infestation
      • Pediculus
        • pubis (any site)
    • Infestation
      • Phthirus (pubis) (any site)
    • Infestation
      • pubic, louse
    • Lice(infestation)
      • crab
    • Lice(infestation)
      • pubic (Phthirus pubis)
    • Pediculosis(infestation)
      • pubis (pubic louse) (any site)
    • Pediculosis(infestation)
      • vulvae
    • Phthiriasis(pubis)

Clinical ClassificationClinical

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

CCSR INF009
Parasitic, other specified and unspecified infections
Default principal diagnosis: inpatient Yes · outpatient Yes

Patient EducationClinical

Parasitic Diseases

Parasites are living things that use other living things - like your body - for food and a place to live. You can get them from contaminated food or water, a bug bite, or sexual contact. Some parasitic diseases are easily treated and some are not.

Read the full article at MedlinePlus

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

Convert B85.3 to ICD-9-CMHistory

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

ICD-9-CM
132.2 Phthirus pubis
Exact Match The mapping is direct, with no qualifiers.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About B85.3Overview

Is B85.3 (Pediculosis and phthiriasis) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report phthiriasis on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does B85.3 group to?

When phthiriasis is the principal diagnosis on an inpatient stay, it groups to MS-DRG 606, 607, with relative weights from 0.9064 to 1.5132 depending on complications. Higher weights mean higher Medicare reimbursement.

What is the ICD-9 equivalent of B85.3?

Under the General Equivalence Mappings, phthiriasis converts to ICD-9-CM 132.2 (phthirus pubis). The mapping is a direct match.

Footnotes

[1] Not chronic - A diagnosis code that does not fit the criteria for chronic condition (duration, ongoing medical treatment, and limitations) is considered not chronic. Some codes designated as not chronic are acute conditions. Other diagnosis codes that indicate a possible chronic condition, but for which the duration of the illness is not specified in the code description (i.e., we do not know the condition has lasted 12 months or longer) also are considered not chronic.