G44.02 Chronic cluster headacheNon-billable header with 2 child codes.
G44.1 Vascular headache, not elsewhere classified ("cluster headache (G44.0)")G43 Migraine ("headache syndromes (G44.-)")G89 Pain, not elsewhere classified ("headache syndromes (G44.-)")R51 Headache ("migraine and other headache syndromes (G43-G44)")G44.001 Cluster headache syndrome, unspecified, intractableG44.009 Cluster headache syndrome, unspecified, not intractableG44.01 Episodic cluster headacheG44.011 Episodic cluster headache, intractableG44.019 Episodic cluster headache, not intractableG44.02 Chronic cluster headache (this code)G44.021 Chronic cluster headache, intractableG44.029 Chronic cluster headache, not intractableG44.03 Episodic paroxysmal hemicraniaG44.031 Episodic paroxysmal hemicrania, intractableG44.039 Episodic paroxysmal hemicrania, not intractable