Gallery of Photos of Psoriasis

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.

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).

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.

The problem with gluteal involvement is that the very act of sitting can irritate inflamed skin and make the condition worse.

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.

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:

• Eczema
• Erythrasma
• Lichen planus
• Lupus
• Pityriasis rosea
• Ringworm
• Seborrheic dermatitis
• Squamous cell carcinoma
• Tinea capitis
• Tinea curis (jock Itch)
• Tinea pedis (athletes foot)

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.

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 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.

Because these diseases are more common in childhood, children tend to be affected than adults. Adults under 30 are also vulnerable.

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).

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).