Hey Guz,

Thanks for the update and good question... In six years of working with over 500 CHers taking the anti-inflammatory regimen, there is almost always a reason why this regimen doesn't work or stops working...

The leading culprits are allergic reactions, some kind of infection, surgery & Trauma and finally, prescription medications that interfere with the vitamin D3 capacity to prevent CH.  It can also be a combination of the above that keeps the anti-inflammatory regimen from preventing CH.

A good first-generation anti-histamine like Benadryl (Diphenhydramine HCL) works if the problem is an allergy.  Diphenhydramine crosses the blood brain barrier (BBB) to block H1 histamine receptors on brain cells and this enables vitamin D3 to do its thing to prevent CH. 

If the allergy continues unchecked, it triggers Mast Cells in the brain to release a flood of histamine.   The histamine in turn, triggers the release of CGRP from neurons in the hypothalamus and trigeminal ganglia.   CGRP is the nasty neuropeptide that causes neurogenic inflammation and the terrible pain we know as a cluster headache.  It gets worse.  CGRP triggers Mast cells to release more histamine in a circular chain reaction that continues until the reactants are consumed and the headache stops... for a while. 

Pollen in the spring time and leaf mold spores in the fall are common allergens.  That said, chemical pollutants, dust mites, animal dander, household mold spores in air handler filters and under the refrigerator are also common triggers of allergic reactions.

If the problem is an allergy, I've recently found that 12.5 mg (5 mL) of Children's Liquid Benadryl (Diphenhydramine HCL) in the morning and another 12.5 mg in the evening prior to bed works like a champ to block H1 histamine receptors and stop the circular chain reaction. 

Once the allergic reaction has been stopped, vitamin D3 is capable of preventing CH.  You should note that in many cases, allergic reactions are sub-clinical, i.e., no obvious or outward symptoms... but the allergy is still there.

Keep taking the Benadryl (Diphenhydramine HCL) for a week.  If there's no joy or favorable change in CH patterns after a week of Benadryl, an allergy may not be the problem.

If the problem is an infection and in particular, a viral infection... additional vitamin D3 in the form of a 50,000 IU/day loading dose for five days plus a 1000 mg tablet of vitamin C every two hours throughout the day for a total of 6 grams should slow viral infections to the point where vitamin D3 can start preventing CH.

Just like with allergies, some viral infections can be sub-clinical.

If you've had a bacterial infection and were prescribed an antibiotic, you need to start taking a good probiotic.  Antibiotics are indiscriminate so kill off friendly symbiotic colonies of bacteria and biota living in the GI tract called the microbiome.  A good probiotic will help rebuild these friendly colonies of bacteria.  In short, a happy gut is a healthy gut as close to 70% of the human immune system resides in and around the GI tract.  Keep taking the probiotic until the bottle is empty...

Trauma and surgery are obvious problems.  If you've been banged up or had recent surgery, a week of 50,000 IU/day vitamin D3 loading doses should do the trick in elevating depleted vitamin D3 levels.

Finally, there's Curcumin (Turmeric).  Curcumin is another potent natural anti-inflammatory agent that works with Vitamin D3 to help prevent CH.  500 mg/day curcumin for a few weeks should do the trick.

You can give the above a try one at a time or go for broke and start all of them...  dealer's choice.

Take care and please keep us posted.

V/R, Batch