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?
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
- Psoriatic arthritis--Joint inflammation that
produces symptoms of arthritis in patients who have or will develop
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.
- Calcipotriene--This drug is a synthetic form of
vitamin D3 that can be applied to the skin. Applying calcipotriene ointment
(for example, Dovonex*) twice a day controls the speed of turnover of skin
cells. Because calcipotriene can irritate the skin, however, it is not
recommended for use on the face or genitals. It is sometimes combined with
topical corticosteroids to reduce irritation. Use of more than 100 grams of
calcipotriene per week may raise the amount of calcium in the body to
* Brand names are provided as examples
only, and their inclusion does not mean that these products are endorsed by the
National Institutes of Health or any other Government agency. Also, if a
particular brand name is not mentioned, this does not mean or imply that the
product is unsatisfactory.
- Retinoid--Topical retinoids are synthetic forms of
vitamin A. The retinoid tazarotene (Tazorac) is available as a gel or cream
that is applied to the skin. If used alone, this preparation does not act as
quickly as topical corticosteroids, but it does not cause thinning of the
skin or other side effects associated with steroids. However, it can
irritate the skin, particularly in skin folds and the normal skin
surrounding a patch of psoriasis. It is less irritating and sometimes more
effective when combined with a corticosteroid. Because of the risk of birth
defects, women of childbearing age must take measures to prevent pregnancy
when using tazarotene.
- 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). Coal tar is less effective than corticosteroids and many
other treatments and, therefore, is sometimes combined with ultraviolet B (UVB)
phototherapy for a better result. The most potent form of coal tar may
irritate the skin, is messy, has a strong odor, and may stain the skin or
clothing. Thus, it is not popular with many patients.
- Anthralin--Anthralin reduces the increase in skin
cells and inflammation. Doctors sometimes prescribe a 15- to 30-minute
application of anthralin ointment, cream, or paste once each day to treat
chronic psoriasis lesions. Afterward, anthralin must be washed off the skin
to prevent irritation. This treatment often fails to adequately improve the
skin, and it stains skin, bathtub, sink, and clothing brown or purple. In
addition, the risk of skin irritation makes anthralin unsuitable for acute
or actively inflamed eruptions.
- 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. Often, it is more
effective when combined with topical corticosteroids, anthralin, or coal
- Clobetasol propionate--This is a foam topical
medication (Olux), which has been approved for the treatment of scalp and
body psoriasis. The foam penetrates the skin very well, is easy to use, and
is not as messy as many other topical medications.
- Bath solutions--People with psoriasis may find
that adding oil when bathing, then applying a moisturizer, soothes their
skin. Also, individuals can remove scales and reduce itching by soaking for
15 minutes in water containing a coal tar solution, oiled oatmeal, Epsom
salts, or Dead Sea salts.
- Moisturizers--When applied regularly over a long
period, moisturizers have a soothing effect. Preparations that are thick and
greasy usually work best because they seal water in the skin, reducing
scaling and itching.
Natural ultraviolet light from the sun and controlled delivery of artificial
ultraviolet light are used in treating psoriasis.
- Sunlight--Much of sunlight is composed of bands of
different wavelengths of ultraviolet (UV) light. When absorbed into the
skin, UV light suppresses the process leading 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. Daily, short, nonburning
exposure to sunlight clears or improves psoriasis in many people. Therefore,
exposing affected skin to sunlight is one initial treatment for the disease.
- 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.
A newer type of UVB, called narrowband UVB, emits the part of the
ultraviolet 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). It is gaining in
popularity because it does help and is more convenient than PUVA. 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 once each week 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 phototherapy (PUVA)--This
treatment combines oral or topical administration of a medicine called
psoralen with exposure to ultraviolet A (UVA) light. UVA has a long
wavelength that penetrates deeper into the skin than UVB. Psoralen makes the
skin more sensitive to this light. PUVA is normally used when more than 10
percent of the skin is affected or when the disease interferes with a
person's occupation (for example, when a teacher's face or a salesperson's
hands are involved). 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 shortterm 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 for one to two days with UVA-absorbing
glasses. Long-term treatment is associated with an increased risk of
squamous-cell and, possibly, melanoma skin cancers. Simultaneous use of
drugs that suppress the immune system, such as cyclosporine, have little
beneficial effect and increase the risk of cancer.
- Light therapy combined with other therapies--Studies
have shown that combining ultraviolet light treatment and a retinoid, like
acitretin, adds to the effectiveness of UV light for psoriasis. For this
reason, if patients are not responding to light therapy, retinoids may be
added. UVB phototherapy, for example, may be combined with retinoids and
other treatments. One combined therapy program, referred to as the Ingram
regime, involves a coal tar bath, UVB phototherapy, and application of an
anthralin-salicylic acid paste that is left on the skin for 6 to 24 hours. A
similar regime, the Goeckerman treatment, combines coal tar ointment with
UVB phototherapy. Also, PUVA can be combined with some oral medications
(such as retinoids) to increase its effectiveness.
For more severe forms of psoriasis, doctors sometimes prescribe medicines that
are taken internally by pill or injection. This is called systemic treatment.
Recently, attention has been given to a group of drugs called biologics (for
example, alefacept and etanercept), which are made from proteins produced by
living cells instead of chemicals. They interfere with specific immune system
- 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
clotenhancing 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). It is sometimes combined with
PUVA or UVB treatments. Methotrexate should not be used by pregnant women,
or by women who are planning to get pregnant, because it may cause birth
- Retinoids--A retinoid, such as acitretin (Soriatane),
is a compound with vitamin A-like properties that may be prescribed for
severe cases of psoriasis that do not respond to other therapies. Because
this treatment also may cause birth defects, women must protect themselves
from pregnancy beginning 1 month before through 3 years after treatment with
acitretin. Most patients experience a recurrence of psoriasis after these
products are discontinued.
- 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. The best candidates for this therapy are those
with severe psoriasis who have not responded to, or cannot tolerate, other
systemic therapies. 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. It should not be given with phototherapy.
- 6-Thioguanine--This drug is nearly as effective as
methotrexate and cyclosporine. It has fewer side effects, but there is a
greater likelihood of anemia. This drug must also be avoided by pregnant
women and by women who are planning to become pregnant, because it may cause
- Hydroxyurea (Hydrea)--Compared with methotrexate
and cyclosporine, hydroxyurea is somewhat less effective. It is sometimes
combined with PUVA or UVB treatments. Possible side effects include anemia
and a decrease in white blood cells and platelets. Like methotrexate and
retinoids, hydroxyurea must be avoided by pregnant women or those who are
planning to become pregnant, because it may cause birth defects.
- Alefacept (Amevive)--This is the first biologic
drug approved specifically to treat moderate to severe plaque psoriasis. It
is administered by a doctor, who injects the drug once a week for 12 weeks.
The drug is then stopped for a period of time while changes in the skin are
observed and a decision is made regarding the need or further treatment.
Because alefacept suppresses the immune system, the skin often improves, but
there is also an increased risk of infection or other problems, possibly
including cancer. Monitoring by a doctor is required, and a patient's blood
must be tested weekly around the time of each injection to make certain that
T cells and other immune system cells are not overly depressed.
- Etanercept (Enbrel)--This drug is an approved
treatment for psoriatic arthritis where the joints swell and become
inflamed. Like alefacept, it is a biologic response modifier, which after
injection blocks interactions between certain cells in the immune system.
Etanercept limits the action of a specific protein that is overproduced in
the lubricating fluid of the joints and surrounding tissues, causing
inflammation. Because this same protein is overproduced in the skin of
people with psoriatic arthritis, patients receiving etanercept also may
notice an improvement in their skin. Individuals should not receive
etanercept treatment if they have an active infection, a history of
recurring infections, or an underlying condition, such as diabetes, that
increases their risk of infection. Those who have psoriasis and certain
neurological conditions, such as multiple sclerosis, cannot be treated with
this drug. Added caution is needed for psoriasis patients who have
rheumatoid arthritis; these patients should follow the advice of a
rheumatologist regarding this treatment.
- Antibiotics--These medications are not indicated
in routine treatment of psoriasis. However, antibiotics may be employed when
an infection, such as that caused by the bacteria Streptococcus, triggers an
outbreak of psoriasis, as in certain cases of guttate psoriasis.
There are many approaches for treating psoriasis. Combining various topical,
light, and systemic treatments often permits lower doses of each and can result
in increased effectiveness. Therefore, doctors are paying more attention to
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
What Are Some Promising Areas of Psoriasis Research?
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. 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). Several of these
drugs are awaiting approval by the U.S. Food and Drug Administration (FDA).
Advances in laser technology are making it possible for doctors to experiment
with laser light treatment of localized plaques. A UVB laser was recently tested
in a study that was conducted at several medical centers. Although improvements
in the skin were noted, this treatment is not without possible side effects. In
some patients, the skin became inflamed, blistered, or discolored following
Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS)
National Institutes of Health
1 AMS Circle
Bethesda, MD 20892–3675
Nutritional and Herbal Therapy for
- Omega-3 fatty acids (oily fish, flaxseed oil,
1,000 mg two times a day) may reduce inflammation and regulate
- Zinc (30 mg a day) and copper
- Folic acid (400 mcg a day) is important in
- Quercetin (500 mg three times a day before meals)
- It's important to avoid inflammatory foods such as meat,
dairy, simple sugars, acidic foods (tomato, oranges, coffee) and allergic
foods such as corn, wheat, citrus, eggs, etc).
- Avoid alcohol and smoking
- Reishi mushroom is a superior immune booster and
regulator and can, therefore, be helpful in controlling psoriasis.
- According to the
Tao of Nutrition, a natural remedy for psoriasis is to apply
mashed garlic to the affected areas, changing twice a day for one week.
Dr. Li's Protective Moisturizer
can help relieve skin dryness and
Tao of Nutrition, by Maoshing Ni, Ph.D., C.A., and Cathy McNease,