Questions and Answers about Psoriasis
What Is Psoriasis?
Psoriasis is a chronic (long-lasting) skin disease of scaling and inflammation that affects 2 to 2.6 percent of the United States population, or between 5.8 and 7.5 million people. 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?
- What Causes Psoriasis?
- How Is Psoriasis Diagnosed?
- How Is Psoriasis Treated?
- What Are Some Promising Areas of Psoriasis Research?
- Where Can People Find More Information About Psoriasis?
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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:
- 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.
- Psoriatic arthritis -- Joint inflammation that produces symptoms of arthritis in patients who have or will develop psoriasis.
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How is Psoriasis Treated?
Doctors generally treat psoriasis in steps based on the
severity of the disease, size of the areas involved, type of psoriasis,
and the patient's response to initial treatments. This is sometimes
called the "1-2-3" approach. In step 1, medicines are applied to the
skin (topical treatment). Step 2 uses light treatments (phototherapy).
Step 3 involves taking medicines by mouth or injection that treat the
whole immune system (called systemic therapy).
Over time, affected skin can become resistant to
treatment, especially when topical corticosteroids are used. Also, a
treatment that works very well in one person may have little effect in
another. Thus, doctors often use a trial-and-error approach to find a
treatment that works, and they may switch treatments periodically (for
example, every 12 to 24 months) if a treatment does not work or if
adverse reactions occur.
Topical Treatment
Treatments applied directly to the skin may improve its
condition. Doctors find that some patients respond well to ointment or
cream forms of corticosteroids, vitamin D3, retinoids, coal tar, or
anthralin. Bath solutions and moisturizers may be soothing, but they are
seldom strong enough to improve the condition of the skin. Therefore,
they usually are combined with stronger remedies.
- Corticosteroids--These drugs reduce inflammation and
the turnover of skin cells, and they suppress the immune system.
Available in different strengths, topical corticosteroids (cortisone)
are usually applied to the skin twice a day. Short-term treatment is
often effective in improving, but not completely eliminating, psoriasis.
Long-term use or overuse of highly potent (strong) corticosteroids can
cause thinning of the skin, internal side effects, and resistance to the
treatment's benefits. If less than 10 percent of the skin is involved,
some doctors will prescribe a high-potency corticosteroid ointment.
High-potency corticosteroids may also be prescribed for plaques that
don't improve with other treatment, particularly those on the hands or
feet. In situations where the objective of treatment is comfort,
medium-potency corticosteroids may be prescribed for the broader skin
areas of the torso or limbs. Low-potency preparations are used on
delicate skin areas. (Note: Brand names for the different strengths of
corticosteroids are too numerous to list in this booklet.)
- Calcipotriene--This drug
