ICD-10 Code B46.1 – Rhinocerebral Mucormycosis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B46.1 – Rhinocerebral mucormycosis
What it is
B46.1 identifies rhinocerebral mucormycosis, a serious fungal infection that involves the nose, sinuses, and nearby facial or brain structures. You use it when documentation specifies this invasive form of mucormycosis.
Clinical signs
Clinical features vary; refer to documentation. Commonly reported findings include sinus pain, nasal discharge, facial swelling, black necrotic tissue, and possible eye or neurologic involvement when the infection spreads.
When to use this code
Use B46.1 when the provider documents rhinocerebral mucormycosis, rhino-orbital-cerebral mucormycosis, or an equivalent invasive sinonasal fungal infection. Code it from confirmed diagnoses, discharge summaries, or specialist notes when the infection is clearly identified. Check documentation if the record only says “fungal sinusitis” or “mucormycosis” without site.
Do not use for
Do not use B46.1 for simple sinusitis, superficial fungal infection, or mucormycosis limited to another site. If the site is unspecified or unclear, check documentation before assigning this code.
Coding tip
Code the documented anatomic site exactly; if the record does not clearly show rhinocerebral involvement, do not assume it.