Psoriasis is a relatively common inflammatory skin condition. In fact, approximately 125 million people worldwide, 2 to 3 percent of the total population, have psoriasis. Despite its lengthy status, the condition is still largely a mystery. So what is psoriasis? And what types of psoriasis do doctors define?
What is psoriasis?
Psoriasis is a chronic, inflammatory disorder by nature that attacks multiple systems in the body including the skin and the joints. The characteristic marker of psoriasis is hyperproliferation (over growth) of the epidermal layer of skin. Psoriasis most commonly manifests itself on the skin of the elbows, knees, scalp, lumbosacral areas, intergluteal clefts, and glans of the penis. All types of psoriasis have similar histological characteristics. At some point during the disease, psoriasis develops into characteristic plaques.
Types of psoriasis
Most types of psoriasis causes patches of thick, red skin with silvery scales. These patches are often found on the elbows, knees, scalp and trunk of the body. But the skin problems can also show up other places such as fingernails, toenails, genitals, and inside the mouth. Psoriasis presents in a variety of forms:
Erythrodermic - appears on the skin as a widespread reddening and exfoliation of fine scales, often accompanied by severe itching, swelling and pain
Guttate psoriasis - characterized by small red dots of psoriasi that often appear on the trunk, arms and legs after medical event such as a streptococcal infection or viral upper respiratory infection
Inverse psoriasis - localized in the skin folds; this type of psoriasis does not manifest scaling but appears as smooth inflamed lesions that are subject to irritation due to rubbing and sweating
Nail psoirasis - appears as pits in the finger or toenails; nails can also develop a yellowish color and become thick, crumble easily, be surrounded by inflammation or detach from the nail bed
Plaque psoriasis - the most common type of psoriasis; characterized by raised, inflamed (red) lesions covered with a silvery white scale that can appear on any skin surface ( knees, elbows, scalp, and trunk are the most common locations)
Psoriatic arthritis - a form of arthritis that causes inflammation and swelling primarily in the hands, feet or in larger joints such as the knees, hips, elbows, and the spine; can cause stiffness, pain, and joint damage
Pustular psoriasis - characterized by cyclical pustules, or blister-like lesions of noninfectious pus, made of white blood cells in the skin that are either localized or widespread
Scalp psoriasis - plaque psoriasis localized on the scalp characterized by elevated, inflamed, lesions covered with silvery white scales
Do doctors know what causes psoriasis? And can you avoid contracting it? Learn more about risk factors and causes of psoriasis in the next section on Psoriasis Causes here.