Psoriasis
October 2013
Questions and Answers about Psoriasis
This publication contains general information about psoriasis. It
describes what psoriasis is, what causes it, and what the treatment
options are. If you have further questions after reading this
publication, you may wish to discuss them with your doctor.
What Is Psoriasis?
Psoriasis is a chronic (long-lasting) skin disease of scaling and
inflammation that affects greater than 3 percent of the U.S. 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,
some 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 concerns about intimate
relationships. 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. Sometimes people who have psoriasis notice that lesions
will appear where the skin has experienced trauma. The trauma could be
from a cut, scratch, sunburn, or infection.
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. Erythrodermic psoriasis can be very serious and requires
immediate medical attention.
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 don’t necessarily have to occur at the
same time.
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, where the
psoriasis is located, and the patient’s response to initial treatments.
Treatment can include:
1
- medicines applied to the skin (topical treatment)
- light treatment (phototherapy)
- medicines by mouth or injection (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 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 D
3, retinoids, coal tar, or
anthralin. Bath solutions and lubricants may be soothing, but they are
seldom strong enough to improve the condition of the skin. Therefore,
they usually are combined with stronger remedies.
- Topical corticosteroids. These drugs reduce
inflammation and the turnover of skin cells, and they suppress the
immune system. Corticosteroids are typically recommended for active
outbreaks of 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.
- Vitamin D analogs. Synthetic forms of vitamin D
control the speed of turnover of skin cells. Excessive use of these
creams may raise the amount of calcium in the body to unhealthy levels.
- Retinoids. Topical retinoids are synthetic forms of
vitamin A. Because of the risk of birth defects, women of childbearing
age must take measures to prevent pregnancy when using retinoids.
- Coal tar. Preparations containing coal tar (gels
and ointments) may be applied directly to the skin, added (as a liquid)
to the bath, or used on the scalp as a shampoo. Coal tar products are
available in different strengths, and many are sold over the counter
(not requiring a prescription). The most potent form of coal tar may
irritate the skin, is messy, has a strong odor, and may stain the skin
or clothing.
- Anthralin. Anthralin reduces the increase in skin
cells and inflammation. Doctors may prescribe daily application of
anthralin ointment, cream, or paste for brief periods to treat chronic
psoriasis lesions. Afterward, anthralin must be washed off the skin to
prevent irritation. It discolors skin, bathtub, sink, clothing, and most
surfaces.
- Salicylic acid. This peeling agent, which is
available in many forms such as ointments, creams, gels, and shampoos,
can be applied to reduce scaling of the skin or scalp.
- Bath solutions. People with psoriasis may find
that adding oil when bathing, then applying a lubricant, soothes their
skin. Also, individuals can remove scales and reduce itching by soaking
in water containing a coal tar solution, oiled oatmeal, Epsom salts, or
Dead Sea salts.
- Lubricants. When applied regularly over a long
period, lubricants have a soothing effect. Preparations that are thick
and greasy usually work best because they seal water in the skin,
reducing scaling and itching.
Light Therapy
Natural ultraviolet (UV) light from the sun and controlled delivery
of artificial UV light are used in treating psoriasis. It is important
that light therapy be administered by a doctor. Spending time in the sun
or a tanning bed can cause skin damage, increase the risk of skin
cancer, and worsen symptoms.
- Sunlight. Much of sunlight is composed of bands of
different wavelengths of UV light. When absorbed into the skin, UV light
suppresses the process Fleading to disease, causing activated T cells
in the skin to die. This process reduces inflammation and slows the
turnover of skin cells that causes scaling.
- Ultraviolet B (UVB) phototherapy. UVB is light with
a short wavelength that is absorbed in the skin’s epidermis. An
artificial source can be used to treat mild and moderate psoriasis. Some
physicians will start treating patients with UVB instead of topical
agents. A UVB phototherapy, called broadband UVB, can be used for a few
small lesions, to treat widespread psoriasis, or for lesions that resist
topical treatment. This type of phototherapy is normally given in a
doctor’s office by using a light panel or light box. Some patients use
UVB light boxes at home under a doctor’s guidance.
Another type of UVB, called narrowband UVB, emits the part of the UV
light spectrum band that is most helpful for psoriasis. Narrowband UVB
treatment is superior to broadband UVB, but it is less effective than
PUVA treatment (see next paragraph). At first, patients may require
several treatments of narrowband UVB spaced close together to improve
their skin. Once the skin has shown improvement, a maintenance treatment
may be all that is necessary. However, narrowband UVB treatment is not
without risk. It can cause more severe and longer lasting burns than
broadband treatment.
- Psoralen and ultraviolet A (UVA) phototherapy (PUVA).
This treatment combines oral or topical administration of a medicine
called psoralen with exposure to UVA light. UVA has a long wavelength
that penetrates deeper into the skin than UVB. Psoralen makes the skin
more sensitive to this light. Compared with broadband UVB treatment,
PUVA treatment taken two to three times a week clears psoriasis more
consistently and in fewer treatments. However, it is associated with
more short-term side effects, including nausea, headache, fatigue,
burning, and itching. Care must be taken to avoid sunlight after
ingesting psoralen to avoid severe sunburns, and the eyes must be
protected with UVA-absorbing glasses. Long-term treatment is associated
with an increased risk of squamous-cell and, possibly, melanoma skin
cancers.
Systemic Treatment
For more severe forms of psoriasis, doctors sometimes prescribe
medicines that are taken internally by pill or injection. This is called
systemic treatment.
- Methotrexate. Like cyclosporine, methotrexate slows
cell turnover by suppressing the immune system. It can be taken by pill
or injection. Patients taking methotrexate must be closely monitored
because it can cause liver damage and/or decrease the production of
oxygen-carrying red blood cells, infection-fighting white blood cells,
and clot-enhancing platelets. As a precaution, doctors do not prescribe
the drug for people who have had liver disease or anemia (an illness
characterized by weakness or tiredness due to a reduction in the number
or volume of red blood cells that carry oxygen to the tissues).
Methotrexate should not be used by pregnant women, or by women who are
planning to get pregnant, because it may cause birth defects.
- Retinoids. Oral retinoids are compounds with
vitamin A-like properties that may be prescribed for severe cases of
psoriasis that do not respond to other therapies. Because these
medications also may cause birth defects, women must protect themselves
from pregnancy.
- Cyclosporine. Taken orally, cyclosporine acts by
suppressing the immune system to slow the rapid turnover of skin cells.
It may provide quick relief of symptoms, but the improvement stops when
treatment is discontinued. Its rapid onset of action is helpful in
avoiding hospitalization of patients whose psoriasis is rapidly
progressing. Cyclosporine may impair kidney function or cause high blood
pressure (hypertension). Therefore, patients must be carefully
monitored by a doctor. Also, cyclosporine is not recommended for
patients who have a weak immune system or those who have had skin
cancers as a result of PUVA treatments in the past.
- Biologic response modifiers. Biologics are made
from proteins produced by living cells instead of chemicals. They
interfere with specific immune system processes which cause the
overproduction of skin cells and inflammation. These drugs are injected
(sometimes by the patient). Patients taking these treatments need to be
monitored carefully by a doctor. Because these drugs suppress the immune
system response, patients taking these drugs have an increased risk of
infection, and the drugs may also interfere with patients taking
vaccines. Also, some of these drugs have been associated with other
diseases (like central nervous system disorders, blood diseases, cancer,
and lymphoma) although their role in the development of or contribution
to these diseases is not yet understood. Some are approved for adults
only, and their effects on pregnant or nursing women are not known.
Combination Therapy
Combining various topical, light, and systemic treatments often
permits lower doses of each and can result in increased effectiveness.
There are many approaches for treating psoriasis. Ask the doctor about
the best options for you. Find out:
- How long the treatment may last.
- How long it will take to see results.
- What the possible side effects are.
- What to do if the side effects are severe.
Psychological Support
Some individuals with moderate to severe psoriasis may benefit from
counseling or participation in a support group to reduce
self-consciousness about their appearance or relieve psychological
distress resulting from fear of social rejection.
What Research Is Being Conducted on Psoriasis?
Researchers are trying to learn how skin cells form in order to
create healthy skin. At the same time, others are looking at the cells
and mechanisms which cause lesions in the skin. If any of these
mechanisms can be interrupted, researchers may find a way to stop the
disease process.
Significant progress has been made in understanding the inheritance
of psoriasis. A number of genes involved in psoriasis are already known
or suspected. In a multifactor disease (involving genes, environment,
and other factors), variations in one or more genes may produce a
greater likelihood of getting the disease. Researchers are continuing to
study the genetic aspects of psoriasis, and some studies are looking at
the nervous system to determine the genes responsible for the circuitry
that causes itching.
Since discovering that inflammation in psoriasis is triggered by T
cells, researchers have been studying new treatments that quiet immune
system reactions in the skin. Among these are treatments that block the
activity of T cells or block cytokines (proteins that promote
inflammation). If researchers find a way to target only the
disease-causing immune reactions while leaving the rest of the immune
system alone, resulting treatments could benefit psoriasis patients as
well as those with other autoimmune diseases.
Research has suggested that psoriasis patients may be at greater risk
of cardiovascular problems, especially if the psoriasis is severe, as
well as obesity, high blood pressure, and diabetes. Researchers are
trying to determine the reasons for these associations and how best to
treat patients.
More information on research is available from the following websites:
- NIH Clinical Research Trials and You
helps people learn more about clinical trials, why they matter, and how
to participate. Visitors to the website will find information about the
basics of participating in a clinical trial, first-hand stories from
actual clinical trial volunteers, explanations from researchers, and
links to how to search for a trial or enroll in a research-matching
program.
- ClinicalTrials.gov
offers up-to-date information for locating federally and privately
supported clinical trials for a wide range of diseases and conditions.
- NIH RePORTER
is an electronic tool that allows users to search a repository of both
intramural and extramural NIH-funded research projects from the past 25
years and access publications (since 1985) and patents resulting from
NIH funding.
- PubMed
is a free service of the U.S. National Library of Medicine that lets
you search millions of journal citations and abstracts in the fields of
medicine, nursing, dentistry, veterinary medicine, the health care
system, and preclinical sciences.
Where Can People Find More Information About Psoriasis?
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Information Clearinghouse
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
Phone: 301-495-4484
Toll free: 877-22-NIAMS (877-226-4267)
TTY: 301-565-2966
Fax: 301-718-6366
Email:
NIAMSinfo@mail.nih.gov
Website:
http://www.niams.nih.gov
If you need more information about available resources in your
language or another language, please visit our website or contact
the NIAMS Information Clearinghouse at
NIAMSinfo@mail.nih.gov.
Other Resources
American Academy of Dermatology
Website: http://www.aad.org
National Psoriasis Foundation
Website: http://www.psoriasis.org
Acknowledgments
The NIAMS gratefully acknowledges the assistance of the following
individuals in the preparation and review of the original version of
this publication: Kevin D. Cooper, M.D., University Hospitals of
Cleveland/Case Western Reserve University, Cleveland, OH; Gerald
Krueger, M.D., University of Utah, Salt Lake City, UT; Mark Lebwohl,
M.D., Mount Sinai Medical Center, New York, NY; Laurence H. Miller,
M.D., P.A., Chevy Chase, MD; Alan N. Moshell, M.D., NIAMS/NIH; Robert
Stern, M.D., Beth Israel Deaconess Medical Center, Boston, MA; and
National Psoriasis Foundation, Portland, OR.
The mission of the National Institute of Arthritis and
Musculoskeletal and Skin Diseases (NIAMS), a part of the U.S. Department
of Health and Human Services’ National Institutes of Health (NIH), is
to support research into the causes, treatment, and prevention of
arthritis and musculoskeletal and skin diseases; the training of basic
and clinical scientists to carry out this research; and the
dissemination of information on research progress in these diseases. The
NIAMS Information Clearinghouse is a public service sponsored by the
NIAMS that provides health information and information sources.
Additional information can be found on the NIAMS website at
www.niams.nih.gov.
For Your Information
This publication contains information about medications used to treat
the health condition discussed here. When this publication was
developed, we included the most up-to-date (accurate) information
available. Occasionally, new information on medication is released.
For updates and for any questions about any medications you are taking, please contact
-
U.S. Food and Drug Administration
Toll free: 888-INFO-FDA (888-463-6332)
Website: http://www.fda.gov
For additional information on specific medications, visit Drugs@FDA at
http://www.accessdata.fda.gov/scripts/cder/drugsatfda. Drugs@FDA is a searchable catalog of FDA-approved drug products.
For updates and questions about statistics, please contact
-
Centers for Disease Control and Prevention, National Center for Health Statistics
Website: http://www.cdc.gov/nchs
This publication is not copyrighted. Readers are encouraged to duplicate and distribute as many copies as needed.
Additional copies of this publication are available from:
-
National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
Information Clearinghouse
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892-3675
Phone: 301-495-4484
Toll free: 877-22-NIAMS (877-226-4267)
TTY: 301-565-2966
Fax: 301-718-6366
Email: NIAMSinfo@mail.nih.gov
Website: http://www.niams.nih.gov
NIH Publication No. 13–5040
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(Instituto Nacional de Alergias y Enfermedades Infecciosas)
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