Psoriasis is a skin condition that causes overgrowth of skin cells. In people with psoriasis, skin cells mature more rapidly than they are supposed to and they build up as a layer of scaly, inflamed skin. Experts think that psoriasis is an autoimmune disease with genetic influences. That is, the disease is actually caused by the immune system attacking skin cells and causing changes in the skin that cause rapid maturation of skin cells. Scientific research has shown that a type of immune system cell called a T cell is overactive in people with psoriasis.
Psoriasis can run in families, and certain things can trigger outbreaks of psoriasis in susceptible individuals. These factors include: increased levels of stress, infections, injury to areas of the skin, sunburn, exposure to cold weather, dry skin, alcohol consumption in excess, smoking and the use of some prescription drugs. People with other immune system problems, such as HIV infection, or those on chemotherapy for cancer treatment are also more likely to develop psoriasis. People may struggle with psoriasis, a chronic skin disease, for the rest of their lives, but the disease may flare up at times and be barely noticeable at others. It is possible to have remission periods with no psoriasis symptoms. The onset of psoriasis is usually during young adulthood between the ages of 15 to 35. However, anyone can develop psoriasis. The rarest age group for psoriasis onset is infants, but there have been cases reported of psoriasis in infants. The psoriasis rash is not contagious, but its appearance may deter others.
There are several different subcategories of psoriasis. The most common manifestation of psoriasis is called plaque psoriasis. Plaque psoriasis is categorized by the formation of scaly, red patches of skin. The skin that flakes off of these inflamed areas may appear scaly and silvery. In mild cases, there may be a little bit of skin flaking, like dandruff. In severe cases, these areas of inflamed skin can be large and even painful. The areas, called plaques, are raised and may be itchy. Depending on the case, the plaques can be localized or more widespread throughout the body. They can appear pretty much anywhere that there is skin, including the inside lining of the mouth and on the genitals. Psoriasis can also affect the scalp and the nails. Nails that are affected by psoriasis may become discolored, pitted, crumbly and may even separate from the nail bed. People suffering from psoriasis may be more likely to contract bacterial skin infections due to itching the inflamed areas of skin.
There are other types of psoriasis, which are all less common than plaque psoriasis. Pustular psoriasis causes blisters either in localized areas or in larger areas of the body. These blisters form rapidly and go away after a few days, but they may keep forming repeatedly.
Guttate psoriasis involves the appearance of small, pink-colored spots on the trunk of the body, limbs and scalp. These spots are not quite as dry, thick and red as the plaques that characterize plaque psoriasis. Guttate psoriasis is often triggered by an infection, such as a respiratory infection or strep throat. It is possible for Guttate psoriasis to occur once along with an infection and never return, but some people have repeated cases.
Inverse psoriasis causes inflammation of certain skin areas without formation of raised plaques. Inverse psoriasis is often found in the groin area, under the armpits, and in other areas in which one layer of skin overlaps another. For instance, in women and overweight men with inverse psoriasis, the fold underneath the breasts may become inflamed.
Erythrodermic psoriasis is the most severe and most rare form of psoriasis. This type of psoriasis causes a widespread rash that may cover most of the surface area of the skin on the body. This rash may peel, itch and burn like a sunburn. Erythrodermic psoriasis can be triggered by certain medications and sunburn, and it may occur in individuals with poor control over their psoriasis.
In some cases of psoriasis, the individual may also suffer from joint inflammation (arthritis), leading to painful, stiff joints. This is called psoriatic arthritis, and this condition can also cause other problems, such as inflammation of the eye (conjunctivitis). Some cases of psoriatic arthritis only affect one joint, while others may affect many joints. Most cases are not severe enough to cause permanent disability, and psoriatic arthritis is often less severe than other autoimmune causes of arthritis such as rheumatoid arthritis, but it can lead to progressive joint damage if untreated. Acute pain from arthritis also makes it difficult for a person to get around. Psoriatic arthritis occurs in some form in about 33 percent of individuals with psoriasis.