Psoriasis is the most prevalent autoimmune disease in the U.S., affecting as many as 7.5 million Americans. In simplest terms, psoriasis is a chronic skin condition that is characterized by rough, flaky skin and severe dry patches, with symptoms often worsening in harsh winter climates. It occurs when the immune system sends out faulty signals resulting in red, scaly patches on the skin that bleed and itch. Psoriasis is not contagious.

Psoriasis frequently occurs with a range of other health concerns including Crohn’s disease, diabetes, hypertension, heart attack, depression and liver disease.

Up to 30 percent of people with psoriasis also develop psoriatic arthritis, which causes pain, swelling and stiffness around the joints. People with mild psoriasis are just as likely to develop psoriatic arthritis as those with moderate or severe forms of the disease.

Psor-iasis flare-ups are more common during colder, dryer winter months, but also during times of emotional stress or other illness, such as a cold or the flu. Though psoriasis is not contagious, it can often take an emotional toll on suffers if the psoriasis patches are noticeable — especially for children and teens.

Psoriasis ranges in severity from the mildest form, with just very small patches of irritation to raw, disfiguring patches across large portions of the body. In more extreme cases, psoriasis can also cause joint pain and tenderness, called psoriatic arthritis. Though the exact cause of psoriasis is unknown, current treatments are effective at controlling the length and severity of flare-ups.

In most cases, your doctor can properly diagnose psoriasis by just looking at the affected area. They may want to do a skin test, however, to rule out a fungal infection. If your psoriasis is moderate to severe, or inhibits your lifestyle, your doctor may prescribe medication to help prevent or lessen the severity of flare-ups.

Lynda Metz is the director of community development at Bonner General Hospital. The information in this article was provided courtesy of the National Psoriasis Foundation.