Skip main navigation



What is psoriasis?


Psoriasis is a chronic skin condition in which skin cells develop and flake off more rapidly than normal, causing dry and red areas of skin that are covered with silvery scaling. These areas of dry skin are called plaques. They can be the size of a thumbnail or cover large areas, such as the back or buttocks, and can occur anywhere on the skin. Psoriasis plaques are most likely to appear on the scalp, elbows, knees, trunk, buttocks, and back.

Psoriasis causes

Although it's not fully known what causes psoriasis, it's thought to be related to the body's immune system. One type of white blood cell called the T-lymphocyte, a cell that normally travels through the body to detect and fight foreign diseases and substances, attacks healthy skin cells instead. This attack is what causes an in an increased production of both skin cells, leading to the plague growth on the skin from overactive skin production. Psoriasis also tends to run in families and is more likely to affect people with white skin. Psoriasis can affect people of all ages, but typically first appears in youth to middle age. It is not contagious.

Psoriasis prognosis

Psoriasis affects 1 to 3% of people living in the U.S. It is characterized by periods of remission with flare-ups in which symptoms worsen. It's believed that sunburn or other injury to the skin, certain medications, and other factors can cause flare-ups. Although psoriasis is a chronic disease with no cure, early treatment may help keep it from becoming more severe.

Back to Ask a Pharmacist


Answers to questions regarding information about medications or health conditions are not for diagnostic or treatment purposes and are not conclusive as to the presence or absence of any health condition. Consult your physician for diagnosis and treatment of your medical condition. The information provided is not a substitute for medical advice. Advances in medicine may cause this information to become outdated, invalid or subject to debate. Professional opinions and interpretations of the scientific literature may vary. Walgreens' terms of use and general warranty disclaimer apply to all services provided. If you are in need of immediate medical attention, contact your physician, poison control center or emergency medical professional. If you need to speak with a pharmacist for non-emergency matters, contact your local Walgreens pharmacist or call a pharmacist toll-free at 1 (877) 250-5823.

Your Digital Health Advisor. Powered by WebMD. Manage diabetes with this easy online tool.* Get started.
Your Digital Health Advisor. Powered by WebMD. Manage diabetes with this easy online tool.* Get started.

Balance Rewards for Healthy Choices

20 Points
20 Points

Now you can track your blood pressure and blood glucose.

Start earning points Go Arrow