Chances are in your favor that they are CH, BUT late onset Clusters can also mimic other, more serious problems. Would strongly suggest seeing a headache specialist for a work-up.
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Cephalalgia. 2010 Apr;30(4):399-412. Epub 2010 Feb 15.

Cluster-like headache. A comprehensive reappraisal.
Mainardi F, Trucco M, Maggioni F, Palestini C, Dainese F, Zanchin G.

Headache Centre, Neurological Division, SS. Giovanni e Paolo Hospital, Venice, Italy. federico.mainardi@ulss12.ve.it

Abstract
Among the primary headaches, cluster headache (CH) presents very particular features allowing a relatively easy diagnosis based on criteria listed in Chapter 3 of the International Classification of Headache Disorders (ICHD-II). However, as in all primary headaches, possible underlying causal conditions must be excluded to rule out a secondary cluster-like headache (CLH). THE OBSERVATION OF SOME CASES WITH CLINICAL FEATURES MIMICKING PRIMARY CH, BUT OF SECONDARY ORIGIN, led us to perform an extended review of CLH reports in the literature. We identified 156 CLH cases published from 1975 to 2008. THE MORE FREQUENT PATHOLOGIES IN ASSOCIATION WITH CLH WERE THE VASCULAR ONES (38.5%, N = 57), FOLLOWED BY TUMOURS (25.7%, N = 38) AND INFLAMMATORY INFECTIOUS DISEASES (13.5%, N = 20). Eighty were excluded from further analysis, because of inadequate information. The remaining 76 were divided into two groups: those that satisfied the ICHD-II diagnostic criteria for CH, 'fulfilling' group (F), n = 38; and those with a symptomatology in disagreement with one or more ICHD-II criteria, 'not fulfilling' group (NF), n = 38. Among the aims of this study was the possible identification of clinical features leading to the suspicion of a symptomatic origin. In the differential diagnosis with CH, red flags resulted both for F and NF, older age at onset; for NF, abnormal neurological/general examination (73.6%), duration (34.2%), frequency (15.8%) and localization (10.5%) of the attacks.

WE STRESS THE FACT THAT, ON FIRST OBSERVATION, 50% OF CLH PRESENTED AS F CASES, PERFECTLY MIMICKING CH. THEREFORE, THE IMPORTANCE OF ACCURATE, CLINICAL EVALUATION AND OF NEUROIMAGING CANNOT BE OVERESTIMATED.

PMID: 19735480 [PubMed
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LOCATING HEADACHE SPECIALIST

1. Search the OUCH site (button on left) for a list of recommended M.D.s.

2. Yellow Pages phone book: look for "Headache Clinics" in the M.D. section and look under "neurologist" where some docs will list speciality areas of practice.

3.  Call your hospital/medical center. They often have an office to assist in finding a physician. You may have to ask for the social worker/patient advocate.

4. Multimedia File Viewing and Clickable Links are available for Registered Members only!!  You need to or ; On-line screen to find a physician.

5. Multimedia File Viewing and Clickable Links are available for Registered Members only!!  You need to or Look for "Physician Finder" search box. They will send a list of M.D.s for your state.I suggest using this source for several reasons: first, we have read several messages from people who, even seeing neurologists, are unhappy with the quality of care and ATTITUDES they have encountered; second, the clinical director of the Jefferson (Philadelphia) Headache Clinic said, in late 1999, that upwards of 40%+ of U.S. doctors have poor training in treating headache and/or hold attitudes about headache ("hysterical female disorder") which block them from sympathetic and effective work with the patient; third, it's necessary to find a doctor who has experience, skill, and a set of attitudes which give hope of success. This is the best method I know of to find such a physician.

6. Multimedia File Viewing and Clickable Links are available for Registered Members only!!  You need to or NEW certification program for "Headache Medicine" by the United Council for Neurologic Subspecialties, an independent, non-profit, professional medical organization.
        Since this is a new program, the initial listing is limited and so it should be checked each time you have an interest in locating a headache doctor.

Hi Mike,  I am from eastern PA, originally Ohio. I first had a CH 8 years ago at the age of 45. It lasted 3 months. Luckily I was diagnosed fast as I was working at a pharma company working on a team for headache meds. I was fast tracked to Jefferson Headache Center as we worked with the head of the dept. Well, after 8 years, I got hit again. My family doc had me tested for temporal arteritis (not sure of the spelling) as it mimics CH's. Also had the standard MRI. All tests were negative so he ruled in favor of the CH. Now that I'm not working at the pharma I don't have an appointment at Jefferson until Feb (very difficult to get in with the top docs). I am working with a local neuro who did the MRI.  Good luck and I hope you're pain free soon.  Prednisone has helped me.

Gidget