2027 ICD-10-CM Diagnosis Code B35.1Tinea unguium
ICD-10-CM Codes›A00–B99›B35-B49›B35
- Billable — Valid for Submission
- Not Chronic
B35.1 is a billable ICD-10-CM diagnosis code for tinea unguium. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 606 through 607. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Fungal infections.
Code Identity
Code Classification
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Distal and lateral subungual onychomycosis
- Endonyx onychomycosis
- Fusarium infection
- Infection of skin caused by Neoscytalidium dimidiatum
- Infection of toenail
- Nail bed infection
- Neoscytalidium dermatomycosis
- Onycholysis
- Onycholysis due to fungal infection of nail
- Onychomycosis
- Onychomycosis caused by Acremonium
- Onychomycosis caused by Botryodiplodia theobromae
- Onychomycosis caused by Curvularia lunata
- Onychomycosis caused by Epidermophyton floccosum
- Onychomycosis caused by Fusarium
- Onychomycosis caused by mold
- Onychomycosis caused by Neocucurbitaria unguis-hominis
- Onychomycosis caused by Neoscytalidium dimidiatum
- Onychomycosis caused by Onychocola canadensis
- Onychomycosis caused by Pseudeurotium ovale
- Onychomycosis caused by Scopulariopsis brevicaulis
- Onychomycosis caused by Trichophyton interdigitale
- Onychomycosis caused by Trichophyton mentagrophytes
- Onychomycosis caused by Trichophyton rubrum
- Onychomycosis caused by Trichophyton schoenleinii
- Onychomycosis caused by Trichophyton soudanense
- Onychomycosis caused by Trichophyton tonsurans variant tonsurans
- Onychomycosis caused by Trichophyton violaceum
- Onychomycosis due to dermatophyte
- Onychomycosis due to opportunistic infection
- Onychomycosis of nail of digit
- Onychomycosis of toenails
- Proximal subungual onychomycosis
- Superficial white onychomycosis
- Tinea caused by Epidermophyton floccosum
- Tinea caused by Trichophyton interdigitale
- Tinea caused by Trichophyton mentagrophytes
- Tinea caused by Trichophyton rubrum
- Tinea caused by Trichophyton soudanense
- Tinea caused by Trichophyton tonsurans
- Tinea caused by Trichophyton violaceum
- Total dystrophic onychomycosis
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to B35.1: its own notes plus those printed at B35, block B35-B49, 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.
- favus
- infections due to species of Epidermophyton, Micro-sporum and Trichophyton
- tinea, any type except those in B36.-
- 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.
- Dermatophytic onychia
- Dermatophytosis of nail
- Onychomycosis
- Ringworm of nails
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.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
nails B35.1
Onychia See Also: Cellulitis, digit;
dermatophytic B35.1
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Onychomycosis
a fungal infection of the nail, usually caused by dermatophytes; yeasts; or nondermatophyte molds.
Patient EducationClinical
Tinea Infections
Tinea is the name of a group of diseases caused by a fungus. Types of tinea include ringworm, athlete's foot and jock itch. These infections are usually not serious, but they can be uncomfortable. You can get them by touching an infected person, from damp surfaces such as shower floors, or even from a pet.
Read the full article at MedlinePlus
Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.
Convert B35.1 to ICD-9-CMHistory
The closest ICD-9-CM equivalents under the General Equivalence Mappings.
Code HistoryHistory
Questions About B35.1Overview
What is the ICD-10 code for tinea unguium?
The ICD-10-CM code for tinea unguium is B35.1 (sometimes written as B351). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is B35.1 (Dermatophytosis) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report tinea unguium on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does B35.1 group to?
When tinea unguium is the principal diagnosis on an inpatient stay, it groups to MS-DRG 607, 606, with relative weights from 0.8772 to 1.5721 depending on complications. Higher weights mean higher Medicare reimbursement.
What is the ICD-9 equivalent of B35.1?
Under the General Equivalence Mappings, tinea unguium converts to ICD-9-CM 110.1 (dermatophytosis of nail). The mapping is a direct match.
