What Is Psoriasis?
Psoriasis is a chronic (long-lasting) skin disease of scaling and inflammation that affects greater
than 3 percent of the United States population, or more than 5 million adults. 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. Although it is not unusual for the skin around affected joints to crack, about 30 percent of those 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 many 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, called flares, then improves. Conditions that may cause flares include infections, stress, and changes in climate that dry the skin. Also, certain medicines, including beta-blockers, which are prescribed for high blood pressure, and lithium 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:
Plaque psoriasis. Skin lesions are red at the base and covered by silvery scales.
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).
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.
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.
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.
Another condition in which people may experience psoriasis is psoriatic arthritis. This is a form of arthritis that produces the joint inflammation common in arthritis and the lesions common in psoriasis. The joint inflammation and the skin lesions donít necessarily have to occur at the same time.
Is risk for skin infections higher in people with psoriasis than in people with normal skin?
Studies have shown that psoriatic plaques and adjacent normal skin usually have the same type of bacteria, but the number of bacteria per square millimeter is higher in the psoriatic plaques. This, in itself, is usually not an increased risk for secondary infections.
Risk for secondary infections may increase with hard scratching as this abrades the skin and opens it to bacterial invasion. Hard scratching should be avoided for this reason, and because abrasion of the skin can trigger formation of new psoriatic lesions.
A skin hygiene program recommended by a dermatologist is usually adequate to keep bacterial populations in check. Specific anti-bacterial measures may be prescribed by a dermatologist when such measures are warranted.
Symptoms of secondary infection are redness of skin around a psoriatic lesion or increased redness of the lesion, increased warmth in the skin and/or pus in the skin in the area of a lesion. Fever, malaise, and light-headedness can be symptoms of a serious systemic infection.
Will psoriasis shorten my life?
Psoriasis itself does not appear to shorten a personís life. Patients with psoriasis should be able to live full lives into their senior years.
Will psoriasis cause my hair to fall out?
Psoriasis itself will not cause the hair to fall out. However, very thick scales in the scalp can entrap hair and as you attempt to remove the scales, you can loose hair in the process. In addition, some medications such as salicylic acid can temporarily damage the hair.
Should I change my psoriasis skin care regimen during the winter?
Itís important to increase your use of moisturizing creams and ointments during the winter, applying heavy layers, especially over the skin affected by psoriasis. It is helpful to apply the moisturizing cream while your skin is damp. Also, be sure to pat yourself dry after bathingódonít rub yourself with the towel.
During the winter months, the humidity is generally lower, especially in homes with forced air heating. This tends to cause dry, itchy skin. Scratching affected skin will worsen your psoriasis and can even cause new lesions to form. Thus, it is important not to scratch, pick, or scrub psoriasis lesions.
Is it true that getting a skin scrape can lead to a psoriatic lesion?
Yes. Psoriasis patients can develop lesions at the site of significant skin trauma, especially during a period of active disease. Psoriasis worsens in areas of skin scrapes, scratches, and cuts (such as surgical wounds). Thatís why it is so important not to pick, scratch, or scrub the lesions and scales. The development of a psoriatic lesion at the site of skin trauma is called Koebnerís phenomenon.
What treatments are the best for me?
No single psoriasis treatment works for everyone, but something will work for most people. It is hard to predict what will work for a particular individual; however, it is important to be open-minded and willing to work with your doctor to find a treatment that will work for you.