Zygomycosis (B46) ICD-10-CM
The B46 code range covers zygomycosis with 9 ICD-10-CM diagnosis codes. 8 of them are billable and valid for claim submission in fiscal year 2026, and the category headers group them but cannot themselves be billed.
Codes in the B46 Range 9 codes · 8 billable
Clinical Terms in This Code Range
Definitions from the National Library of Medicine for conditions coded in the B46 range.
Mucormycosis
Infection in humans and animals caused by any fungus in the order MUCORALES (e.g., RHIZOPUS; MUCOR; CUNNINGHAMELLA; APOPHYSOMYCES; ABSIDIA; SAKSENAEA and RHIZOMUCOR) There are many clinical types associated with infection including central nervous system, lung, gastrointestinal tract, skin, orbit and paranasal sinuses. In humans, it usually occurs as an OPPORTUNISTIC INFECTION.
Zygomycosis
Infection in humans and animals caused by fungi in the class Zygomycetes. It includes MUCORMYCOSIS and entomophthoramycosis. The latter is a tropical infection of subcutaneous tissue or paranasal sinuses caused by fungi in the order Entomophthorales. Phycomycosis, closely related to zygomycosis, describes infection with members of Phycomycetes, an obsolete classification.
About the B46 Code Range
ICD-10 code B46 and its subcodes are specific to diagnosing different forms of zygomycosis, a rare but serious fungal infection caused by molds in the order Mucorales. These codes cover infections affecting various body systems, including the lungs, brain and sinuses, skin, gastrointestinal tract, as well as disseminated and unspecified forms of zygomycosis.
This section clarifies the appropriate use of codes such as B46.0 for pulmonary mucormycosis (a lung infection), B46.1 for rhinocerebral mucormycosis (affecting the nose, sinuses, and brain), and B46.3 for cutaneous mucormycosis (skin infections also known as subcutaneous zygomycosis). The use of synonyms like "fungal infection of cerebrum" and "necrotizing cutaneous mucormycosis" helps medical coders identify the precise condition when encountering these alternate terms. Other codes such as B46.2 for gastrointestinal mucormycosis and B46.4 for disseminated mucormycosis include infections spreading through the digestive system or multiple organs. When the exact site or species is not identified, B46.5 or B46.9 are used. This comprehensive coding set ensures accurate medical records and treatment documentation for these life-threatening fungal infections.
Questions About This Page
How many billable codes are in the B46 range?
Of the 9 codes in this range, 8 are billable and valid for claim submission from October 1, 2025 through September 30, 2026. Category header codes group them but cannot be reported on claims.
What does the B46 range classify?
The range classifies zygomycosis. Each code links to its own reference page with billing status, MS-DRG grouping, coding notes, and clinical information.
Related References
Source: CMS FY 2026 ICD-10-CM Tabular List and order file, effective October 1, 2025 through September 30, 2026.
