ICD-10 Code B05.1 – Measles complicated by meningitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B05.1 – Measles complicated by meningitis
What it is
B05.1 identifies measles with meningitis as a documented complication. Use it when the record shows measles infection and inflammation of the meninges are both present.
Clinical signs
Typical measles features include fever, cough, coryza, conjunctivitis, and rash. Meningitis may add headache, neck stiffness, photophobia, vomiting, or altered mental status; clinical features vary, refer to documentation.
When to use this code
Use this code when the provider documents measles complicated by meningitis, or when meningitis is clearly linked to the measles infection. It applies to confirmed diagnoses, not merely suspected exposure. If the chart does not specify the complication, check documentation.
Do not use for
Do not use B05.1 for uncomplicated measles, or for meningitis without documented measles. If another cause of meningitis is identified, code that condition instead.
Coding tip
Verify that the complication is explicitly tied to measles in the provider note before assigning B05.1.