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Psoriasis is a common condition where the skin gets red and scaly; psoriasis can cause itching, discomfort, and sometimes pain.
Psoriasis affects 2% to 4% of the world’s population. While it can begin at any age, psoriasis has 2 peaks of onset, the first at age 20 to 30 years and the second at age 50 to 60 years. It affects men and women equally but is more common in non-Hispanic whites. Some patients are more prone to developing psoriasis, especially if there is a family member with psoriasis. External factors such as infection, smoking, and certain medications can make psoriasis worse in some patients.
Psoriasis is associated with a number of medical conditions. One-third of patients with psoriasis develop psoriatic arthritis, a progressive joint disease that can limit movement if untreated. Patients with severe psoriasis are also at higher risk than the general population for high blood pressure, diabetes, heart attacks, strokes, obesity, and depression.
Different types of psoriasis exist, including plaque, guttate, erythrodermic, and pustular psoriasis. Among them, plaque psoriasis is the most common type. Plaque psoriasis appears as red, thick, scaly, raised-up areas on the skin that are itchy, painful, and can flake and bleed. While plaque psoriasis can involve any part of the body, it commonly appears on the scalp, elbows, knees, trunk, and buttocks. Other types of psoriasis can look different and affect different areas of the body, such as nails, skin folds, or palms and soles. A patient with psoriatic arthritis often feels prolonged stiffness in the joints in the morning or during long periods of inactivity.
Your doctor will ask you about your skin and joint symptoms, family history, and environmental exposures, such as recent infections, medications, or habits that may affect psoriasis. Your doctor will examine your skin and may need to do a skin biopsy.
Many treatment options exist for psoriasis. The treatment choice depends on the severity of psoriasis and whether you have psoriatic arthritis or other medical conditions. For mild or localized psoriasis, topical treatments, such as topical corticosteroids and topical vitamin D, are commonly used. For moderate to severe psoriasis, 3 categories of treatments are considered—phototherapy, oral medications, and biologic medications. Phototherapy, or light therapy, uses specific ultraviolet light wavelengths to treat psoriasis. Phototherapy is typically given 2 to 3 times per week in a dermatologist’s office. Both oral and biologic medications are systemic medications, which means that they affect not only the skin but also other parts of the body. Biologic medications reduce specific inflammation molecules that are abnormally elevated in psoriasis. Most biologic medications are delivered via injections into the fat layer of the skin and can result in substantial improvement of psoriasis.
National Psoriasis Foundationhttps://www.psoriasis.org/
American Academy of Dermatologyhttps://www.aad.org/
Conflict of Interest Disclosures: Dr Armstrong is an investigator for and advisor to AbbVie, Janssen, Novartis, Lilly, and Valeant. No other conflicts are reported.
Armstrong AW. Psoriasis. JAMA Dermatol. 2017;153(9):956. doi:10.1001/jamadermatol.2017.2103
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