You make some very good points, Nick, which I will take to heart.
First, I was not biopsied by the dermatologist who saw me for about 5 minutes, a few weeks ago, but I was "scraped", and she looked at the scrapings under a microscope. I don't think this counts as a biopsy, right?
Good point about questioning whether it is sodium nitrate, vs. red meat. I sure hope you're right about psoriasis patients being able to eat organic red meat, since my hubby is a beefaholic, and eventually, I'd probably succomb to eating beef again! Right now, I'm abstaining from beef, and only eating turkey, chicken, and fish.
You wrote, in regards to the argumentative dermatologist who said milk caused his psoriasis, at your medical conference:
"For a condition to clear up very fast after stopping a particular food, it may also have been an allergic dermatitis and not psoriasis at all....Step 1 in my opinion is to properly determine if you even have psoriasis."
I entirely agree, and am looking for a dermatologist in the Denver area, who can tell me for sure that it is psoriasis. Got any personal recommendations? If anyone else reading this has any personal recommendations, I'm all ears!
You also wrote:
"A more logical approach is to remove one food group at a time, and by a process of ellimination, attempt to work out if a particular good is triggering your psoriasis...."
I'm not sure this would work, in my case. Why? Because I've found that what may work better for me, is to remove a whole bunch of potential "trouble" foods, all at the same time. If I get better, THEN, I'll re-introduce one at a time, to see how I do.
The reason I feel this way, is that for some other conditions, this method has helped me figure out what foods do & don't agree with me. Had I only removed ONE of the SEVERAL trouble foods, I might not have seen or felt enough definite improvement, due to my continuing to eat the OTHER troublesome foods.
I know that this has been the case for others, who have MULTIPLE food "sensitivities" (different from allergies):
For example, if a person has a GLUTEN SENSTIVITIY (gluten is in wheat, rye, barley, & gluten can cross contaminate many samples of oats & buckwheat), possibly along with a CASEIN SENSITIVITY (casein is but one of several milk proteins--another one is "whey"), maybe possibly along with a SENSITIVITY TO CORN PROTEINS &/or a SENSITIVITY TO SOY PROTEINS, &/or a SENSITIVITY TO DIETARY YEAST PROTEINS (A yeast protein sensitivity has been associated in some cases of Crohn's Disease), &/or a SENSITIVITY TO EGG PROTEINS, etc.,
then, such a person may not see positive results until all of the offending proteins are removed simultaneously.
If a person were, instead, to remove the whole shebang all at once, and were to improve,... then, the person could ONE BY ONE, re-introduce each of the above proteins, for a few days, to see which ones agree & don't agree with the person!
Regarding conferences, and doctors thinking each one is always right..., I found lots of arguing and disagreement, among docs (even among the speakers themselves!), at the medical conferences I have attended, and I was rooting for an allergist (in the audience) who begged everyone to pay attention to how food (protein) sensitivities could provoke gastric reflux episodes, causing vocal cords to close up, in what is known as vocal cord dysfunction, paradoxical vocal fold motion, and a dozen other synonyms.
Another allergist stood up, and said he didn't believe in food protein sensitivities! (oh boy!)
Well, today I ate organic turkey left over from Thanksgiving, and I juiced some veggies (organic, fresh, raw ones: carrots, celery, fresh curled parsely, romaine lettuce), and have had some organic (in glass bottles, since I couldn't find these organic fruits available anywhere) grape juice and pineapple juice. I've been drinking my well water, and will eat some organic cooked short grain brown rice, some fresh watercress, some organic almonds, organic raisins, organic figs & organic dates.
When arguing with my hubby, I say, "Don't yell at me. I have psoriasis, and I have to stay calm." That usually works, and he lowers his voice. Of course, I'll have to stop yelling at him, now, too, during arguments! We've been together for over 30 years, and we still don't "get" how eachother's brains work!

Anyway, good luck to you, and to all!
Nick--until all dermatologists stop charging money, when they see psoriasis patients, not diagnosing them properly, knee-jerkishly prescribing steroids etc., never mentioning diet, not even doing a simple blood or urine test, not taking one's blood pressure, not even taking one's temperature, not even mentioning phototherapy at all, etc., do you think that maybe we shouldn't expect the good doc in New Jersey, to stop charging for his book? Just some food for thought.
Carol