Cluster headache is a very severe primary headache disorder. In episodic cluster headache, attacks occur in 'bouts' (clusters) lasting weeks to months. Management of cluster headache entails a combination of attack and prophylactic treatment. Current first choice prophylactic treatment (verapamil) has considerable side effects which can be serious and include possibly fatal cardiac arrhythmias; and it can take weeks to titrate to an effective dose. Evidence has emerged that local steroid injection of the greater occipital nerve (GON) may be effective in cluster headache, but this method has not been investigated as a first line prophylactic treatment in a large, well-documented group of episodic cluster headache patients who are still free of prophylactic medication and just entered a new cluster headache episode. As such, GON-injection has not yet found its way into current treatment protocols. The investigators plan to perform this multicentre double-blind randomized controlled trial to investigate whether GON-injection is efficacious as a first-line prophylactic treatment, aiming to remove the need for high doses of daily medication - such as verapamil - with associated side effects.

Inclusion Criteria:

• Patients have to be diagnosed with episodic cluster headache according to the international classification of headache disorders - third edition, ICHD-3
• Patients have to be aged 18-65 years
• Patients need to be newly diagnosed and treatment naïve, or already diagnosed and currently free from prophylactic treatment
• Patients need to have a mean of 1 or more attacks per day in the 3 days preceding inclusion.
• Patients should be in their cluster period for shorter than 4 weeks before inclusion.

Exclusion Criteria:

• A contraindication for treatment with steroids or verapamil
• The use of anticoagulants or known bleeding disorder.
• Use of any prophylactic medication for cluster headache
• Patients with a history of other primary headache who are currently using prophylactic medication for this headache
• Pregnancy

All Data will be stored using Castor EDC. All hard copies will be stored in the individual centers. If requested, after study completion, data can be shared with de PIs in participating centers.