Psoriasis is a chronic immune-mediated inflammatory disease. It has a peak incidence from 0.1 to 0.3% of the world population and it affects the skin and joints. There is a higher incidence in people with light skin, affecting men and women equally and also affects more people living in colder weather countries, especially those closer to the North Pole.
It’s characterized by skin cells that multiply up to 10 times faster than normal. As underlying cells reach the skin’s surface and die, their sheer volume is raised, red plaques covered with white scales. Psoriasis typically occurs on the knees, elbows, and scalp, and it can also affect the torso, palms, and sole of the feet.
When you have psoriasis, the genes that control your immune system signals get mixed up. Instead of protecting your body from invaders as it is designed to do, it promotes inflammation and turns skin cells on overdrive.
Scientists have found about 25 different genetic mutations in people with psoriasis. It is believed that it takes more than one genetic mutation to cause the disease (polygenetic), and they are looking for the main ones. About 10 in every 100 people have genes that make them more likely to get psoriasis, but only two or three of them actually do.
If you’ve got the right combination of genes, something can turn Psoriasis “on” or start a flare.
1. Patches of red, inflamed skin. These are often covered with loose, silvery scales. They may be itchy and painful, even crack and bleed. In serious cases, they grow and run into each other, making large areas of irritated skin.
2. Fingernail and toenail problems. Your nails may change color or become pitted. They may also begin to crumble or detach from the nail bed.
3. Scalp problems. Patches of scales or crust may form on your head.
In most cases, your primary care doctor or dermatologist will be able to diagnose psoriasis by examining your skin. However, since psoriasis can look like eczema and other skin diseases, diagnosing it can sometimes be difficult. If your doctor isn’t sure whether you have psoriasis, he or she may order a biopsy. Your doctor will remove a small sample of your skin and have it looked by a pathologist.
If you have symptoms of psoriatic arthritis, such as swollen and painful joints, your doctor might run blood tests and take X-rays to rule out other forms of arthritis.