ICD-10 Code B01.12 – Varicella Myelitis (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code B01.12 – Varicella myelitis
What it is
B01.12 identifies myelitis caused by varicella infection. Use it when documentation states spinal cord inflammation is linked to chickenpox or varicella-zoster infection.
Clinical signs
Clinical features vary; refer to documentation. Typical myelitis findings may include weakness, sensory changes, and bowel or bladder dysfunction, with a neurologic exam supporting spinal cord involvement.
When to use this code
Use this code when the provider documents varicella myelitis, varicella-associated spinal cord inflammation, or a clear causal link between varicella and myelitis. It may also apply when the record states myelitis due to chickenpox.
If the note only says “myelitis” without an infectious cause, do not assume B01.12. Check documentation for the specific varicella relationship before coding.
Do not use for
Do not use this code for uncomplicated varicella, encephalitis, or myelitis from another cause. Check documentation when the diagnosis is nonspecific or the infection is not varicella.
Coding tip
Confirm both the neurologic diagnosis and the varicella link in the provider note before assigning B01.12.