Psoriasis signs and symptoms can vary from person to person but may include one or more of the following:
- Red patches of skin covered with silvery scales
- Small scaling spots (commonly seen in children)
- Dry, cracked skin that may bleed
- Itching, burning or soreness
- Thickened, pitted or ridged nails
- Swollen and stiff joints
Psoriasis patches can range from a few spots of dandruff-like scaling to major eruptions that cover large areas. Most types of psoriasis go through cycles, flaring for a few weeks or months, then subsiding for a time or even going into complete remission.
The primary goal of treatment is to stop the skin cells from growing so quickly. While there isn't a cure, psoriasis treatments may offer significant relief. Lifestyle measures, such as using a nonprescription cortisone cream and exposing your skin to small amounts of natural sunlight, also may improve your psoriasis symptoms.
The cause of psoriasis isn't fully known, but it's thought to be related to an immune system problem with cells in your body. More specifically, one key cell is a type of white blood cell called a T lymphocyte or T cell. Normally, T cells travel throughout the body to detect and fight off foreign substances, such as viruses or bacteria. If you have psoriasis, however, the T cells attack healthy skin cells by mistake, as if to heal a wound or to fight an infection.
Overactive T cells trigger other immune responses. The effects include dilation of blood vessels in the skin around the plaques and an increase in other white blood cells that can enter the outer layer of skin. These changes result in an increased production of both healthy skin cells and more T cells and other white blood cells. This causes an ongoing cycle in which new skin cells move to the outermost layer of skin too quickly — in days rather than weeks. Dead skin and white blood cells can't slough off quickly enough and build up in thick, scaly patches on the skin's surface. This usually doesn't stop unless treatment interrupts the cycle.
Just what causes T cells to malfunction in people with psoriasis isn't entirely clear. Researchers have found genes that are linked to the development of psoriasis, but environmental factors also play a role.
Risk Factor
Family history
Perhaps the most significant risk factor for psoriasis is having a family history of the disease. Having one parent with psoriasis increases your risk of getting the disease, and having two parents with psoriasis increases your risk even more.
Viral and bacterial infections
People with HIV are more likely to develop psoriasis than people with healthy immune systems are. Children and young adults with recurring infections, particularly strep throat, also may be at increased risk.
Stress. Because stress can impact your immune system, high stress levels may increase your risk of psoriasis.
Obesity. Excess weight increases the risk of psoriasis. Plaques associated with all types of psoriasis often develop in skin creases and folds.
Smoking. Smoking tobacco not only increases your risk of psoriasis but also may increase the severity of the disease. Smoking may also play a role in the initial development of the disease.
Psoriasis typically starts or worsens because of a trigger that you may be able to identify or avoid. Factors that may trigger psoriasis include:
- Infections, such as strep throat or skin infections
- Injury to the skin, such as a cut or scrape, bugbite or a severe sunburn
- Stress
- Cold weather
- Smoking
- Heavy alcohol consumption
- Certain medications—including lithium, which is prescribed for bipolar disorder, high blood pressure medications such as beta blockers; antimalarial drugs; and iodides
- Psoriatic arthritis
- Eye conditions
- Obesity
- Type 2 diabetes
- Metabolic syndrome
- High blood pressure
- Cardiovascular disease
- Other autoimmune diseases
- Parkinson's disease
- Kidney disease
