- Psoriasis is a chronic (long-lasting) skin
disease of scaling and inflammation.Although the disease occurs in all age
groups, it primarily affects adults. It appears about equally in males and
females. Psoriasis occurs when skin cells quickly rise from their origin
below the surface of the skin and pile up on the surface before they have a
chance to mature. Usually this movement (also called turnover) takes about a
month, but in psoriasis it may occur in only a few days. In its typical
form, psoriasis results in patches of thick, red (inflamed) skin covered
with silvery scales. These patches, which are sometimes referred to as
plaques, usually itch or feel sore. They most often occur on the elbows,
knees, other parts of the legs, scalp, lower back, face, palms, and soles of
the feet, but they can occur on skin anywhere on the body.
The disease may also affect the fingernails, the toenails, and the soft
tissues of the genitals and inside the mouth. While it is not unusual for
the skin around affected joints to crack, approximately 1 million people
with psoriasis experience joint inflammation that produces symptoms of
arthritis. This condition is called psoriatic arthritis.
How Does Psoriasis Affect Quality of Life?
Individuals with psoriasis may experience significant physical discomfort
and some disability. Itching and pain can interfere with basic functions,
such as self-care, walking, and sleep. Plaques on hands and feet can prevent
individuals from working at certain occupations, playing some sports, and
caring for family members or a home. The frequency of medical care is costly
and can interfere with an employment or school schedule. People with
moderate to severe psoriasis may feel self-conscious about their appearance
and have a poor self-image that stems from fear of public rejection and
psychosexual concerns. Psychological distress can lead to significant
depression and social isolation.
What Causes Psoriasis?
Psoriasis is a skin disorder driven by the immune system, especially
involving a type of white blood cell called a T cell. Normally, T cells help
protect the body against infection and disease. In the case of psoriasis, T
cells are put into action by mistake and become so active that they trigger
other immune responses, which lead to inflammation and to rapid turnover of
skin cells. In about one-third of the cases, there is a family history of
psoriasis. Researchers have studied a large number of families affected by
psoriasis and identified genes linked to the disease. (Genes govern every
bodily function and determine the inherited traits passed from parent to
child.) People with psoriasis may notice that there are times when their
skin worsens, then improves. Conditions that may cause flareups include
infections, stress, and changes in climate that dry the skin. Also, certain
medicines, including lithium and betablockers, which are prescribed for high
blood pressure, may trigger an outbreak or worsen the disease.
How Is Psoriasis Diagnosed?
Occasionally, doctors may find it difficult to diagnose psoriasis, because
it often looks like other skin diseases. It may be necessary to confirm a
diagnosis by examining a small skin sample under a microscope. There are
several forms of psoriasis. Some of these include:
o Plaque psoriasis-Skin lesions are red at the base and covered by silvery
scales.
o Guttate psoriasis-Small, drop-shaped lesions appear on the trunk, limbs,
and scalp. Guttate psoriasis is most often triggered by upper respiratory
infections (for example, a sore throat caused by streptococcal bacteria).
o Pustular psoriasis-Blisters of noninfectious pus appear on the skin.
Attacks of pustular psoriasis may be triggered by medications, infections,
stress, or exposure to certain chemicals.
o Inverse psoriasis-Smooth, red patches occur in the folds of the skin near
the genitals, under the breasts, or in the armpits. The symptoms may be
worsened by friction and sweating.
o Erythrodermic psoriasis-Widespread reddening and scaling of the skin may
be a reaction to severe sunburn or to taking corticosteroids (cortisone) or
other medications. It can also be caused by a prolonged period of increased
activity of psoriasis that is poorly controlled.
o Psoriatic arthritis-Joint inflammation that produces symptoms of
arthritis in patients who have or will develop psoriasis.
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