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?
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
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
- 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
- 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
- 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.
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.
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