Skin Health Psoriasis Print Gallery of Photos of Psoriasis Signs and Symptoms You Should Know About By Heather Brannon, MD Updated July 03, 2019 More in Psoriasis Symptoms Diagnosis Treatment Living With Psoriasis is an inflammatory autoimmune disease affecting around 3 percent of the world's population and no less than 2.2 percent of the United States population, according to a 2018 review in Dermatology Research and Practice. Psoriasis is characterized by periodic flares of dry, red skin covered with silvery-white scales (known as plaques). The areas of the body most commonly affected are the back of the forearms, shins, and scalp. There is no cure for psoriasis, and little is known about what actually causes the disease. There are several different types of psoriasis. The following photos depict the two most common types, known as plaque psoriasis and guttate psoriasis. Other luncommon forms include inverse psoriasis, which develops in skin folds, and pustular psoriasis, which manifests with pus-filled lesions. Plaque Psoriasis CDC/Richard S. Hibbets Plaque psoriasis is the most common form of the disease, accounting for 80 percent to 85 percent of all cases. The name references the classic skin lesions that define the disease. Round to oval in shape with clearly defined borders, the plaques most often appear on extensor surfaces. These are areas of skins on the outer side of a joint (as opposed to flexor surfaces on the inner side of a joint where the skin creases). Examples include the back of the forearm near the elbow (as pictured) and the front of the knee. Plaque psoriasis can also develop on the scalp, neck, ears, and just above the buttocks adjacent to the lumbar spine. The plaques tend to be more than half a centimeter (0.2 inches) in diameter and have very thick scales. Topical treatments can help clear plaques by tempering local inflammation and gently loosening the scales. Symptoms of Plaque Psoriasis Plaque Psoriasis of the Elbow CDC/Susan Lindsley This photo illustrates how thick plaques can become if left untreated. Beyond the lack of appropriate treatment, plaque psoriasis can be instigated by any number of common and uncommon triggers. These include stress, infections, obesity, alcohol, smoking, skin trauma, medications, extreme humidity, and cold, dry temperatures. Many of these—drugs and stress especially—can exacerbate flares, making symptoms worse and more difficult to control. In cases this severe, the doctor would likely recommend immunosuppressant drugs that temper the overactive immune response. These include disease-modifying antirheumatic drugs (DMARDs) like methotrexate and cyclosporine or new biologic drugs like Humira (adalimumab) and Enbrel (etanercept). How Plaque Psoriasis Is Treated Plaque Psoriasis of the Gluteal Cleft CDC/Dr. Gavin Hart The gluteal cleft (the crease of skin between the buttocks) is a common site for plaque psoriasis. This photo illustrates the characteristic plaques with their clearly defined borders and patchy scales. The scales are one of the clues that differentiate plaque psoriasis from inverse psoriasis, which can also develop in the gluteal crease. However. with inverse psoriasis, the lesions tend to be smooth with few visible scales. Inverse psoriasis is more common in people with obesity who have more skin folds and greater amounts of adipose (fat-storing) tissues. The problem with gluteal involvement is that the very act of sitting can irritate inflamed skin and make the condition worse. Psoriasis Treatments by Body Part Multiple Psoriatic Plaques CDC/Dr. N.J. Fiumara In this photo, plaque psoriasis appears on the elbow and arm. There is little scaling, but the affected skin appears thick, red and irritated. At first glance, it is easy to mistake the multiple lesions for any number of other skin conditions. Because there are no blood tests or imaging studies that can definitively diagnose psoriasis, misdiagnosis can sometimes occur. The diagnosis of psoriasis is based primarily on the appearance of the lesions, a review of one's medical history (including a family history of psoriasis), and the exclusion of all other causes (referred to as the differential diagnosis). Some of the diseases that mimic psoriasis include: EczemaErythrasmaLichen planusLupusPityriasis roseaRingwormSeborrheic dermatitisSquamous cell carcinomaTinea capitisTinea curis (jock Itch)Tinea pedis (athletes foot) How Plaque Psoriasis Is Diagnosed Plaque Psoriasis of the Trunk CDC/Susan Lindsley It is not uncommon to have psoriatic plaques in areas where clothes are tight, causing friction to the skin. The picture (above) is one such example in which pressure from a belt can give rise to a ring of psoriasis around the waist. The phenomenon, known as the Koebner response, is associated with psoriasis and other diseases in which a rash or lesions will develop along the line of trauma. With psoriasis, a flare may occur as a result of a cut, abrasion, sunburn, rash, or even vigorous scratching. It is even possible for psoriasis to develop on old scar tissues, including tattoos or surgical scars. In this photo, the plaques have begun to heal. Once the lesions have healed, the skin will often lighter or darker than the surrounding skin. In most cases, the discoloration will normalize over time. Guttate Psoriasis Wikimedia Commons/Bobjgalindo Guttate psoriasis is the second most common form of psoriasis, accounting or around 10 percent of cases, according to the National Psoriasis Foundation. The name is derived from the Latin word gutta, which means droplet. It is characterized by small, teardrop-shaped lesions that most usually develop on the trunk but also the arms, legs, and scalp. Guttate psoriasis is often triggered by a bacterial or viral infection. This is especially true with streptococcal infections like strep throat and viral infections like chickenpox and measles. Because these diseases are more common in childhood, children tend to be affected than adults. Adults under 30 are also vulnerable. 6 Common Triggers of Psoriasis Mild Guttate Psoriasis CDC/Susan Lindsley This picture illustrates a mild form of guttate psoriasis. The onset of symptoms is often rapid with multiple lesions erupting on the trunk and extremities in a centripetal pattern (moving from the outside in). Itchiness is common. In addition to infections, certain drugs can trigger a flare. Among the usual suspects are beta-blockers, antimalarial drugs (like Plaquenil), and nonsteroidal anti-inflammatory drugs (especially naproxen). 9 Drugs That Can Trigger Psoriasis Severe Guttate Psoriasis CDC/Dr. Gavin Hart This photo depicts a severe case of guttate psoriasis. As distressing as this may seem, an outbreak is usually self-limiting and will resolve on its own without treatment after several weeks or months. Some people may never experience another episode; others may develop chronic plaque psoriasis that follows them into later adulthood. Because there are no tests to definitively diagnose guttate psoriasis, severe cases like this will typically require a battery of tests to exclude other causes (such as cutaneous T-cell carcinoma or syphilis) and to check for likely triggers (most commonly strep throat or chronic tonsillitis). Psoriasis Doctor Discussion Guide Get our printable guide for your next doctor's appointment to help you ask the right questions. Download PDF Email the Guide Send to yourself or a loved one. Email Address Send There was an error. Please try again. This Doctor Discussion Guide has been sent to . Was this page helpful? Thanks for your feedback! Sign up for our Health Tip of the Day newsletter, and receive daily tips that will help you live your healthiest life. Email Address Sign Up There was an error. Please try again. Thank you, , for signing up. What are your concerns? Other Inaccurate Hard to Understand Submit Article Sources Affandi, A.; Khan, I.; and Saaya, N. Epidemiology and Clinical Features of Adult Patients with Psoriasis in Malaysia: 10-Year Review from the Malaysian Psoriasis Registry (2007–2016). Dermatol Res Prac. 2018;2018:article ID 4371471. DOI: 10.1155/2018/4371471, Brandon, A.; Mufti, A.; Sibbald, G. et al. Diagnosis and Management of Cutaneous Psoriasis: A Review. Adv Skin Wound Care. 2019 Feb;32(2):58-69. DOI: 10.1097/01.ASW.0000550592.08674.43. National Psoriasis Foundation. Guttate Psoriasis. Portland, Oregon.