What is psoriasis?

Another illness that I don't have a ton of info about, but I found a site that does - www.psoriasissolved.com.

There are about eight broad categories of psoriatic symptoms:

Psoriatic Arthritis - Where a person has both psoriasis and arthritis.
Inverse Psoriasis - Smooth patches lying within the folds of skin, often exacerbated due to the presence of candida or fungi.
Erythrodermic Psoriasis - The most uncommon form, and a very serious condition that can lead to blood loss.
Plaque Psoriasis - The most common form, affecting about 90% of all those with psoriasis.
Guttate Psoriasis - Short-lived, and usually affecting those under 30.
Pustular Psoriasis - An uncommon form consisting of pus-filled bumps on the skin.
Scalp Psoriasis - Dry, scaly skin. Often confused with seborrheic dermatitis.
Nail Psoriasis - psoriasis concentrated on fingernails and toenails. The nails become weak and bumpy. May also be related to fungal infections.