Psoriasis is a skin disease that causes red, itchy scaly patches, most commonly on the knees, elbows, trunk and scalp. Psoriasis is the result of a sped-up skin production process. Typically, skin cells grow deep in the skin and slowly rise to the surface. Eventually, they fall off. The typical life cycle of a skin cell is one month. In people with psoriasis, this production process may occur in just a few days. Because of this, skin cells don’t have time to fall off. This rapid overproduction leads to the buildup of skin cells. Scales typically develop on joints, such elbows and knees.
Causes:
Psoriasis is thought to be an immune system problem that causes the skin to regenerate at faster than normal rates. In the most common type of psoriasis, known as plaque psoriasis, this rapid turnover of cells results in scales and red patches.
- Infections, such as strep throat or skin infections
- Weather, especially cold, dry conditions
- Injury to the skin, such as a cut or scrape, a bug bite, or a severe sunburn
- Stress
- Smoking and exposure to secondhand smoke
- Heavy alcohol consumption
- Certain medications — including lithium, high blood pressure medications and antimalarial drugs
- Rapid withdrawal of oral or systemic corticosteroids.
Symptoms:
- Plaque psoriasis.
- Guttate psoriasis.
- Nail psoriasis.
- Inverse psoriasis.
- Pustular psoriasis.
- Erythrodermic psoriasis.
Risk factors:
- Family history.
- Stress.
- Smoking.
How do dermatologists diagnose psoriasis?
To diagnose psoriasis, a dermatologist will examine your skin, nails, and scalp for signs of this condition. Your dermatologist will also ask if you have any:
- Symptoms, such as itchy skin
- Joint problems, such as pain and swelling or stiffness when you wake up
- Blood relatives who have psoriasis
- Recent changes in your life, such as an illness or increased stress.
