ICD-10 Code B46 – Zygomycosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B46 – Zygomycosis
What it is
B46 identifies zygomycosis, also called mucormycosis, a serious fungal infection caused by molds in the order Mucorales. Use it when documentation names this infection or a specific form within it.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include rapidly progressive tissue infection, sinus or nasal involvement, pulmonary disease, or invasive infection in immunocompromised patients.
When to use this code
Use B46 when the provider documents zygomycosis or mucormycosis as the diagnosis. It may apply to rhinocerebral, pulmonary, cutaneous, or disseminated infection if the record supports the fungal etiology.
If the note only describes a suspected fungal infection, check documentation before coding. Confirm that the infection is specifically identified as zygomycosis rather than another mycosis.
Do not use for
Do not use B46 for nonspecific fungal infection or for a different organism without documentation. If the chart does not clearly identify zygomycosis, check documentation.
Coding tip
Code B46 only when the provider explicitly links the infection to zygomycosis or mucormycosis.