B85.3 Phthiriasis

The ICD-10-CM code for Phthiriasis is B85.3 (FY2026). It is a billable, claim-ready diagnosis code.

Classification

Chapter

1: Certain infectious and parasitic diseases (A00-B99)

Section

B85-B89: Pediculosis, acariasis and other infestations (B85-B89)

Category B85

6 codes (5 billable)

FY2026 Status

Stable since FY2024

Also Known As

ICD-10-CM Alphabetic Index entries that lead to B85.3:

• Phthiriasis (pubis)
• Crabs, meaning pubic lice
• Infestation › Phthirus (pubis) (any site)
• Pediculosis (infestation) › pubis (pubic louse) (any site)
• Infestation › pubic, louse
• Lice (infestation) › pubic (Phthirus pubis)
• Infestation › crab-lice
• Lice (infestation) › crab

Inclusion Terms

• Infestation by crab-louse
• Infestation by Phthirus pubis

U.S. Hospital Utilization

• An estimated 220 U.S. inpatient stays in 2023 included B85.3 among the documented diagnoses.

Source: National Inpatient Sample (NIS), Healthcare Cost and Utilization Project (HCUP), Agency for Healthcare Research and Quality, 2016–2023. National survey-weighted estimates.

Official Coding Guidelines

HIV Infections (TOC entry)

a. Human Immunodeficiency Virus (HIV) Infections .............................................................. 19

Infectious agents causing diseases in other chapters (TOC)

b. Infectious agents as the cause of diseases classified to other chapters ................................. 22

Source: CMS — ICD-10-CM Official Guidelines for Coding and Reporting, FY2026

References

• CMS — ICD-10-CM Official Code Set and Guidelines, FY2026
• CDC/NCHS — ICD-10-CM Files and Browser Tool
• AHRQ — HCUP National Inpatient Sample, Frequencies by Diagnosis Code (2016–2023)