ICD-10 Code G44.09 – Other Trigeminal Autonomic Cephalgias (TAC) (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code G44.09 – Other trigeminal autonomic cephalgias (TAC)
What it is
G44.09 identifies trigeminal autonomic headache disorders that do not fit a more specific TAC diagnosis. Use it for documented TAC-type headaches when the record names an “other” category.
Clinical signs
These headaches usually cause severe, unilateral head pain with autonomic features such as tearing, red eye, nasal congestion, or eyelid swelling. Clinical features vary; refer to documentation.
When to use this code
Use this code when the provider documents an other trigeminal autonomic cephalalgia, or a TAC pattern that is not classified elsewhere. It is appropriate when the note supports a TAC diagnosis but does not specify cluster headache or another named subtype. Check documentation if the subtype is unclear.
Do not use for
Do not use G44.09 for migraine, tension-type headache, or a clearly documented cluster headache. If the chart names a different primary headache disorder, code that condition instead.
Coding tip
Code from the provider’s exact headache type and avoid assuming TAC when autonomic symptoms are not documented.