Psoriasis is a skin condition that afflicts around 2-3% of the world population. That means that you probably know a few people who have psoriasis and you might not even realise that they have it. It is probably only if someone has a very bad case of psoriasis that you will become aware of it because most sufferers keep the affected skin covered up and don't talk about it.
It appears as red patches on the skin that become raised above the surrounding area, then can become dry, scaly and itchy. They appear mostly on the lower back, knees, elbows, scalp and in the groin but can appear almost anywhere on the body.
Areas with scars from old injuries seem to be the most likely sites for psoriasis. When I first broke out with psoriasis, it appeared in pretty close to the reverse order to the skin injuries that I had inflicted on myself over the previous 35 years through sports, falls etc. It eventually worked all the way back to my oldest scar, from circumcision at a few days old.
If left untreated the psoriasis patches go beyond redness and itchiness and can crack and bleed. A psoriasis itch is not the mildly annoying little itch that often occurs on normal skin, it can be a painful and very persistent itch. A normal itch will generally go away as soon as it is scratched. A psoriasis itch stays with you, no matter how hard you scratch it. In fact, scratching it can change it from an itch to a burning sensation. The best way to deal with the itch is to resist scratching it. The itch is easier to tolerate than the burn from scratching, so leave it alone. Instead, wipe on a dab of moisturiser or hydro-cortisone cream to soothe the area.
What is happening to cause the redness and raised patches of skin is that the skin is growing too fast in that particular area, at about 6 times the speed that it should. The immune system has received an incorrect message that the particular area is damaged and is trying to repair it, hence the rapid growth. The new skin is pushed toward the surface faster than the natural wearing down and sloughing of the skin can get rid of it, so it builds up the thickness.
In biblical times, psoriasis was thought to be the same as leprosy. So, when you read of lepers being ostricised by society in ancient times, many of them were psoriatics rather than lepers. Be glad that you live in modern more enlightened times but be aware that there are still many people who are shunned by their families and friends due to lack of knowledge.
Psoriasis is entirely non-contagious. Nobody can catch it from anyone else, no-matter how close the contact between them. You cannot catch it by touching someone else, wearing their clothes or even exchanging body fluids through kissing, sex or using the same utensils.
It is an auto-immune condition. It is a defect in the immune system of the person who has psoriasis. This puts it into the same category as arthritis, lupus, type 1 diabetes and many other conditions that have no obvious cause and cannot be passed from one person to another.
It seems on casual thought that the immune system is too strong, trying to repair something that is not damaged. However, this is not so. The immune system is out of balance rather than being too strong. If you treat it by weakening it, you will weaken all aspects of the immune system and open up opportunities for bad things to attack. Instead, you should do all that you can to balance your immune system. Balancing your immune system will weaken those aspects that are too strong and are over-reacting to stimuli and it will strengthen those aspects that are too weak, closing the door for possible infections through those weaknesses.