This is a very broad subject, let me try and explain it in a very simple way. Autoimmune diseases are those diseases where our own defense start attacking our own (host)Skin cells. There are many types of defense cells in our blood. one of them is Lymphocytes. It has two variants, T cell  and B Cell. T Cells produce cytocine and B Cells produce antibody. These antibodies attack any approaching virus or bacteria as shown in figure 1.

FIGURE 1:

FIGURE 2:

Figure 2 is a T cell with a receptor on its surface.

FIGURE 3:

In auto immune diseases our skin develops antigens (Toxins) and presents itself as APC (antigen presenting cells),So our own T cell attack these skin cells .As shown in figure 4.

Here lies the real problem in Psoriatic patients that there own skin is presenting itself like a toxin and our own defense ( T cells and Macrophages ) are attacking it . Figure 4.

FIGURE 4:

Ayurveda has described Autoimmune diseases in great details. Food is the first source of energy for body.

According to Ayurveda, nature has provided us a great system.

Every food we eat takes a long journey to get converted into immunity. This journey to immunity got 8 stages

1. In the digestion process, food gets converted into Rasa Dhatu.
2. From rasa dhatu develops RAKATA(Blood).
3. From rakta develops MASA(muscles).
4. From masa develops MEDA(fat).
5. From meda develops ASTHI(Bones).
6. From asthi develops MAJJA(Bone marrow).
7. From majja develops SHUKRA(semen).
8. From Semen develops the OAJ (Immunity)

Ayurvedic texts has mentioned that it takes 90 days for food to get converted into Shukra (Semen), and another 60 days from Shukra to Oaj (Immunity).
Where any of the above stages are not functioning properly or food as input is contaminated or contains opposite properties or is not digested properly in the first place, it produces all kind of problems in the body. For example instead of producing Rasa Dhatu during digestion process, the system will produces Ama Rasa (toxins or macro globules) . With this every other stage also gets contaminated. For example next stage produces Ama Rakta then Ama Masa, Ama Meda, Ama Asthi, Ama Majja, Ama Shukra and finally Ama Oaj.

Improper digestion leads to ama majja (defective bone marrow ).
Bone marrow is the production center for T cells. (Can you see the chain and main cause for psoriasis?).

Finally Ama Oaj is produced which is an indication of immunodeficiency.
To cure any psoriatic patient permanently it is important to control all the stages of food journey so that all the 7 Dhatus from food (rakat,masa,meda,asthi,majja,shukra and oaj ) are produced in their purest form. By curing Ama majja (defective bone marrow) we are treating the patients at immunity levels. By producing pure OAJ, we are making patients immune to psoriasis triggers.

It is interesting to note here that Ayurveda does not stress upon what you eat as some of the diet controllers look for, instead Ayurvedic text books emphasize on when and how you take your food.

This also explains the modern views where scientific community believes that there is no proven link between diet and its effect on psoriatic conditions but still some patients experience remarkable improvements in their psoriatic conditions with the control of some of the diets and then the same diet control does not produce any effect on other patients and yet the same diet control does not produce any significant effect on same patient after some time. How can we explain this anomaly.

It is because in diet control we are always focused on what to take in our diet and what not to take. Whereas it is the combination of opposite properties of foods which are the cause. when some patients break these combinations unknowingly through diet control exercise they experience improvement in their conditions but when they develop opposite properties in some other combination form their condition deteriorate and diet control fails.

A very visible example is taking fish and milk together which creates flare ups for psoriatic patients and if you are taking milk after 6 hours of taking fish, there will be no aggravation to your psoriatic conditions.

Thus by controlling how and when of your food habits you can control your psoriatic conditions.

Our special Dietary Guideline which we provide to every psoriatic patient under our treatment is based upon above Ayurvedic View and help every psoriatic patients in their early cure.