Problem Skin Part I

For years I've struggled with super dry scalp (other details I will spare you) and have tried so many different products to fix the problem, I've gone to a dermatologist who told me to try something that did not work. So, I did some research of my own and discovered that I have Psoriasis. Thankfully only my scalp is affected, although I have super dry skin as well.
Here is a description of scalp Psoriasis:
Psoriasis is a noncontagious, genetic disease of the
immune system affecting the skin and/or the joints.
According to the National Institutes of Health, as
many as 7.5 million Americans have psoriasis. The
most common form, plaque psoriasis, results in raised,
red lesions covered by silvery white scale. Psoriasis can
be limited to a few lesions or can involve moderate to
large areas of skin.
Scalp psoriasis can be very mild, with slight, fine
scaling. It can also be very severe with thick, crusted
plaques covering the entire scalp. Psoriasis can extend
beyond the hairline onto the forehead, the back of the
neck and around the ears.

There are several products that are available to treat Psoriasis, below are the common ingredients:

Salycic Acid: Salicylic acid is approved by the Food and Drug
Administration (FDA), it softens
scale and makes it easier to remove. It can be used in
combination with tar or other products. Its popular
nickname is “sal acid,” and you will find it both in
over-the-counter (OTC) and prescription products,
mostly in over-the-counter shampoos and soaps.

Tar
Although tars have been classically used to treat psoriasis,
they offer an effective therapy option in treating dandruff as well.
Problems with staining, odor, and messiness in its application
make tar a second-line therapy for most patients.
Tar gelscontain coal tar extract, and they are generally less
messy and smelly than tar itself. Tar shampoos work through
antiproliferative and cytostatic effects, although definitive analy-
ses are difficult because of the large number of biologically
active components in coal tar products. Tar products disperse
scales, which reduce Malassezia (yeasts;high rate of cell turnover) colonization. I've tried Neutrogena's T-Gel which contains 2% Tar extract and it did not help much.

Zinc
It is thought that zinc pyrithione (ZPT) heals the scalp by nor-
malizing epithelial keratinization, sebum production, or both.
Some studies have also shown a significant reduction in the
numbers of yeast organisms after the application of zinc
pyrithione. (I used Pureology's Scalp Cure shampoo (which is 2% Zinc pyrithione) and conditioner for about a year and while I did see a bit of a difference, I still had extreme problems with Psoriasis of the scalp).

What I found while researching treatments was that it's very effective to use a shampoo that has a combination in high percentages of the above ingredients. In other words, drugstore products do not do the trick.
I ordered a shampoo called X-Seb T Plus online for $25, which contains 10% Coal Tar Extract and 3% Salycic Acid. LOVE IT. No more Psoriasis (however it needs to be used continually, otherwise it will return).
When I recived it in the mail, I was alarmed to see that the label said: "Warning: this product contains ingredients known to cause cancer."
...Back I went to doing research...
What I found is that a major concern of many people considering coal tar as a psoriasis therapy is cancer. While occupational exposure to coal tar (miners, asphalt workers, or chimneysweeps for example) may be responsible for some lung, skin, and scrotal cancers, no relationship between even high therapeutic dosages of coal tar for psoriasis and any form of cancer had been established. Some 25-year-long studies have found no increase in any form of cancer over what would be expected without coal tar. HOWEVER, coal tar IS a photosensitzer, which means it makes the skin more sensitive to sun. So if you are planning on using a product that contains coal tar, make sure you wear hair sunscreen or protect your scalp by wearing a hat.

I hope this has been helpful to some of you. Please let me know in the comments or e-mail if any of you have questions.I thought it would be a good thing to share since I spent hours digging for answers for this problem!