Hey Slacker,

That you're still getting whacked by CH taking that much vitamin D3 and Benedryl (Diphenhydramine) suggests a stubborn allergic reaction or a systemic infection of some kind.  The first step is a trip to your PCP for a checkup and lab tests for your serum 25(OH)D, calcium and PTH.  If your 25(OH)D is ≥100 ng/mL, there's no need to increase the vitamin D3 dose.

Benadryl (Diphenhydramine HCL) doesn't stop an allergic reaction.  What it does is block histamine H1 receptors at the genetic layer to slow or stop the effects of histamine released by an allergic reaction.  In our case as CHers, this can help avoid a CGRP cascade.  It appears you're experiencing one now.  During a CGRP cascade none of the CH interventions are effective.

A CGRP cascade can be triggered when an allergen causes mast cells in the trigeminovascular complex to degranulate releasing histamine.  The histamine in turn, causes neurons in the trigeminal gangia to express CGRP and Substance P (SP) which trigger cluster and migraine headache. Both of these neuroactive substances act as allergens causing mast cells to release even more histamine. 

This circular chemical chain reaction results in a flood of CGRP and SP that continues until one or more of the reactants are consumed at which point the CGRP cascade stops and so do CH...  at least until the body recharges mast cells and neurons.

The best course of action involves finding the allergen(s) responsible then minimize your exposure or avoid it completely. You may need the help of an immunologist to ID the offending allergen. Pollen and mold spores are common allergens, but the allergic reactions could easily be caused by a food allergy, a reaction to dust mite poo - dust mites have been with us for thousands of years, or industrial pollutants.

At your present vitamin D3 dose and Benadryl (Diphenhydramine) eliminating the offending allergen can result a rapid decrease in CH frequency.  In short, spending at least 24 hours away from home could result in a cessation of CH if the offending allergen is in your home environment.

Doubling the magnesium and Omega03 fish oil doses for a few days has helped some CHers with similar problems,  Taking 4 to 6 grams a day of liposomal vitamin C and 50 mg/day zinc for a few days can also help reduce the frequency of CH.  If you haven't already done so, taking vitamin B 100 complex has also helped.

Finally, a ketogenic diet with no sugars or wheat products has also helped some CHers break their cycle.

Hope all this helps.  Please keep us posted.

V/R, Batch