Well my experience with doctors was, at around 7 I was diagnosed with eczema due to clusters around my elbows. At around 10 a doctor performed a scraping, which produced pin-prick bleeding that is Auspitz's sign, so pretty much guaranteed psoriasis. At around 17/18, after having had psoriasis for 10 years I went to the doctor because the large patches (some were as large as the palm of my hand) had turned smooth and slightly yellow in the middle, but still appeared to be psoriasis on the outside. He said I'd 'obviously' been misdiagnosed as it was clearly ringworm and he started me on a broadspectrum antifungal.

The antifungal barely worked, but UV is known to be a treatment for both fungal infections and psoriasis. After my first round of antifungals I had a vacation scheduled for the south of France, the infections got better, but when I returned to the UK and by the time I'd got another appointment it'd flared up again. This occurred several times, after my third round I had basically a 2 month vacation in France and no medication. By 6 weeks the ringworm had cleared up and when I returned to the UK my doctor confirmed I was clear.

I visited my regular doctor again (not the one I'd dealt with the ringworm with as he was more specialist, plus on vacation) and she was amazed at my lack of psoriasis, except she confirmed (with a Auspitz's sign) that I still have psoriasis of the scalp.

I've always visited the south of France and Spain and a lot of other mediterranean destinations and none of them ever cleared up my psoriasis, it often went into remission but the scaling remained. So this makes me believe the ringworm (due to it removing a lot of the plaques) allowed the psoriasis to go into complete remission, which removed the food for the ringworm (it had only infected my existing psoriasis and not the rest of my body).

The ringworm left me with discoloration for about a year and I was fortunate enough not to get psoriasis nor ringworm on my nails (they can turn them into claw-like things). I wouldn't advocate it, but 25% of psoriasis patients get a fungal infection, so many might get lucky enough to have it happen to them too. It certainly didn't outright cure it, but I believe it acted as a catalyst of sorts that helped to remove it (I still have psoriasis, but it no longer covers 20% of my body, in fact it only occurs on my scalp, where the ringworm fortunately didn't spread to).

I have, however, read of tape worms being used for the treatment of a few other diseases, including Asthma and IBS (Crohn's specifically IIRC). Incidentally 50% of children with Asthma and eczema/psoriasis have the same defective gene (for filaggrin production), it's also believed Crohn's and hayfever (a condition I also have, but has severely diminished since my psoriasis has cleared from my skin) share the same gene. For asthma and crohn's there is already 'Helminthic therapy' (http://en.wikipedia.org/wiki/Helminthic_therapy), which typically uses pig whipworm, which is only transitory in humans (IE it only lives a short time). Not only does it have higher success rates than medicines, but it also has less severe side effects (hookworm I believe has higher success rates, but causes more people to have side effects and carries slightly worse side effects).

Perhaps in time helminthic therapy will spread to psoriasis treatment, as in theory it should work with any autoimmune disease. Hope this gave you some more info, personally I'd vote for helminthic therapy over ringworm for treating psoriasis, as the side effects of ringworm (whilst generally benign) can be very visual; the discoloration only stayed for about a year with me, but can apparently last considerably longer. I'm sure many women would prefer stomach cramps than potentially life-long discoloration of the skin (at the beginning it seriously looked jaundice in places).