Psoriasis is a skin condition that causes skin redness, silvery scales, and irritation. Most people with psoriasis have thick, red, well-defined patches of skin with flaky, silver-white scales. This is called plaque psoriasis. Psoriasis is most often begins between ages 15 and 35, or as people get older. Psoriasis isn't contagious. This means it doesn't spread to other people. Psoriasis seems to be passed down through families. Susceptibility to psoriasis is linked to HLA genes, specifically the HLA variant called HLA-C*06:02
Evidence shows an association of psoriasis with other autoimmune conditions, such as Crohn's disease and uveitis. It has also been associated with arthritis, depression, inflammatory bowel disease, cardiovascular diseases.
The following may trigger an attack of psoriasis or make it harder to treat:
- Infections from bacteria or viruses, including strep throat
- Dry air or dry skin
- Injury to the skin, including cuts, burns, insect bites, and other skin rashes
- Some medicines, including antimalaria drugs, beta-blockers, and lithium
- Stress
- Psoriasis may be worse in people who have a weak immune system
Related to:
major histocompatibility complex (MHC), autoimmune disease, rash