B35-B49
Medium Complexity
Mycoses
Primary Specialty: Dermatology
Last Updated: 2025-09-09
ICD-10 Codes (115)
115 billable0 category headers
B36Billable
B36.0Billable
B36.1Billable
B36.2Billable
B36.3Billable
B36.8Billable
B36.9Billable
B37Billable
B37.0Billable
B37.1Billable
B37.2Billable
B37.3Billable
B37.31Billable
B37.32Billable
B37.4Billable
B37.41Billable
B37.42Billable
B37.49Billable
B37.5Billable
B37.6Billable
B37.7Billable
B37.8Billable
B37.81Billable
B37.82Billable
B37.83Billable
B37.84Billable
B37.89Billable
B37.9Billable
B38Billable
B38.0Billable
B38.1Billable
B38.2Billable
B38.3Billable
B38.4Billable
B38.7Billable
B38.8Billable
B38.81Billable
B38.89Billable
B38.9Billable
B39Billable
B39.0Billable
B39.1Billable
B39.2Billable
B39.3Billable
B39.4Billable
B39.5Billable
B39.9Billable
B40Billable
B40.0Billable
B40.1Billable
B40.2Billable
B40.3Billable
B40.7Billable
B40.8Billable
B40.81Billable
B40.89Billable
B40.9Billable
B41Billable
B41.0Billable
B41.7Billable
B41.8Billable
B41.9Billable
B42Billable
B42.0Billable
B42.1Billable
B42.7Billable
B42.8Billable
B42.81Billable
B42.82Billable
B42.89Billable
B42.9Billable
B43Billable
B43.0Billable
B43.1Billable
B43.2Billable
B43.8Billable
B43.9Billable
B44Billable
B44.0Billable
B44.1Billable
B44.2Billable
B44.7Billable
B44.8Billable
B44.81Billable
B44.89Billable
B44.9Billable
B45Billable
B45.0Billable
B45.1Billable
B45.2Billable
B45.3Billable
B45.7Billable
B45.8Billable
B45.9Billable
B46Billable
B46.0Billable
B46.1Billable
B46.2Billable
B46.3Billable
B46.4Billable
B46.5Billable
B46.8Billable
B46.9Billable
B47Billable
B47.0Billable
B47.1Billable
B47.9Billable
B48Billable
B48.0Billable
B48.1Billable
B48.2Billable
B48.3Billable
B48.4Billable
B48.8Billable
B49Billable
Updates & Changes
FY 2026 Updates
Current Year
New Codes (1)
B08.62
Orf virus disease with complications
Revised Codes (2)
B00.9
Herpesviral infection, unspecified - updated to include HSV type specification when known
B08.5
Enteroviral vesicular pharyngitis - enhanced diagnostic specificity
Deleted Codes
No codes deleted in this range for FY 2026
Historical Changes
- •FY 2025: Routine maintenance updates with minor terminology clarifications
- •FY 2024: Enhanced specificity requirements for certain code ranges
- •FY 2023: Updated documentation guidelines for improved clarity
Upcoming Changes
- •Proposed updates pending review by Coordination and Maintenance Committee
- •Under consideration: Enhanced digital health integration codes
Implementation Guidance
- •Review all FY 2026 updates for B35-B49 codes before implementation
- •Always verify the most current codes in the ICD-10-CM manual
- •Ensure clinical documentation supports the selected diagnosis codes
- +3 more guidance items...
Range Overview
high priority
The ICD-10 code range B35-B49 is dedicated to Mycoses, a group of diseases caused by fungi. These codes cover a variety of fungal infections, from superficial skin conditions like tinea (ringworm) to systemic diseases like histoplasmosis. The codes are specific, allowing for differentiation between the type of mycoses, the body site affected, and the causative organism.
Key Usage Points:
- •B35-B49 codes are used for all types of fungal infections, regardless of the causative organism.
- •The codes differentiate between superficial and systemic mycoses.
- •Specific codes exist for common conditions like athlete's foot (B35.3) and candidiasis (B37).
- •Some codes require additional codes to specify the causative organism.
- •In some cases, a secondary code may be used to indicate a condition's chronicity or recurrence.
Coding Guidelines
When to Use:
- ✓When a patient presents with a fungal infection, such as ringworm.
- ✓When a patient has a systemic fungal infection, like histoplasmosis.
- ✓When a patient has a recurrent fungal infection.
- ✓When a patient has a fungal infection caused by a specific organism.
When NOT to Use:
- ✗When a patient has a bacterial or viral infection.
- ✗When the causative organism is not a fungus.
- ✗When the infection is not confirmed to be fungal.
- ✗When the patient has a condition that mimics a fungal infection but is not.
Code Exclusions
Always verify exclusions by referencing the patient's medical record and the ICD-10 official guidelines.
Documentation Requirements
Documentation for B35-B49 codes should include the type of mycoses, the body site affected, the causative organism (if known), and any complications or associated conditions. The patient's medical history, physical examination findings, and diagnostic test results should support the chosen code.
Clinical Information:
- •Type of mycoses
- •Body site affected
- •Causative organism
- •Complications or associated conditions
- •Chronicity or recurrence
Supporting Evidence:
- •Medical history
- •Physical examination findings
- •Diagnostic test results
Good Documentation Example:
Patient presents with itchy, red patches on the skin. Diagnosis of tinea corporis confirmed by KOH preparation. B35.4 (Tinea corporis) is coded.
Poor Documentation Example:
Patient presents with skin rash. B35.9 (Dermatophytosis, unspecified) is coded without further investigation or confirmation.
Common Documentation Errors:
- âš Coding a fungal infection without confirmation
- âš Failing to specify the body site affected
- âš Not using additional codes when required
- âš Overlooking chronicity or recurrence
Range Statistics
15
Total Codes
115
Billable
Complexity:
Medium
Primary Use:Clinical Documentation
Chapter:
Coding Complexity
Medium
Complexity Rating
Mycoses codes require a solid understanding of fungal infections and their clinical manifestations. The need to specify the body site, causative organism, and any complications or associated conditions adds to the complexity.
Key Factors:
- â–¸Differentiating between types of mycoses
- â–¸Identifying the body site affected
- â–¸Determining the causative organism
- â–¸Recognizing complications or associated conditions
- â–¸Coding for chronicity or recurrence
Specialty Focus
Mycoses codes are most frequently used in dermatology, infectious disease, and primary care. They are also relevant in specialties dealing with systemic fungal infections, such as pulmonology and hematology.
Primary Specialties:
Dermatology
40%
Infectious Disease
30%
Clinical Scenarios:
- • A patient with HIV presents with oral thrush.
- • A patient with a persistent skin rash is diagnosed with tinea versicolor.
- • A patient with leukemia develops invasive aspergillosis.
- • A patient with chronic athlete's foot has a recurrence.
Resources & References
Numerous resources are available to assist with coding mycoses, including the ICD-10 official guidelines, clinical reference books, and educational materials.
Official Guidelines:
- ICD-10-CM Official Guidelines for Coding and Reporting
- CDC ICD-10-CM Index
- WHO ICD-10 Browser
Clinical References:
- Harrison's Principles of Internal Medicine
- Medscape Reference
Educational Materials:
- AAPC ICD-10 Training
- AHIMA ICD-10 Education
Frequently Asked Questions
Can I code a fungal infection without confirmation?
No, a fungal infection should be confirmed before coding. If the diagnosis is uncertain, consider using a code from the R00-R99 range (Symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified).