G44.021
Chronic cluster headache, intractable
G44.021 (also written G44021) is a billable ICD-10-CM diagnosis code for chronic cluster headache, intractable. It is part of the FY2027 code set, effective October 1, 2026. It is one of the 40 codes in category G44 (Other headache syndromes). The Alphabetic Index lists it under 1 entry. Its coding notes include 1 Excludes1 entry and 12 Excludes2 entries.
Excludes1
Not coded here. The listed conditions generally should not be reported together.
Excludes2
Not included here. Both codes may be reported if the patient has both conditions.
Also from chapter/block level (8 notes)
- certain conditions originating in the perinatal period (P04-P96)
- certain infectious and parasitic diseases (A00-B99)
- complications of pregnancy, childbirth and the puerperium (O00-O9A)
- congenital malformations, deformations, and chromosomal abnormalities (Q00-Q99)
- endocrine, nutritional and metabolic diseases (E00-E88)
- injury, poisoning and certain other consequences of external causes (S00-T88)
- neoplasms (C00-D49)
- symptoms, signs and abnormal clinical and laboratory findings, not elsewhere classified (R00-R94)
Care settings
How CMS programs treat this code. These are CMS claim edits and list entries, not coverage or eligibility rules.
Home Health Primary
Accepted as the primary (principal) diagnosis on a home health claim. The Home Health Grouper assigns it to the MMTA - Other clinical group.
Source: CMS Home Health Grouper Software v07.2.26, effective October 1, 2026Alphabetic Index terms
Terms the official Alphabetic Index lists for this code. 1 entry