Who gets
psoriasis?
How common is psoriasis?
What causes psoriasis?
Is risk for skin infections higher in people with psoriasis than in
people with normal skin?
Is the treatment for psoriasis different for African-Americans and other
darker-skinned people than for people with light-colored skin?
Should I change my psoriasis skin care regimen during the winter?
What effect does the sun have on psoriasis?
Are homeopathic treatments effective for psoriasis?
Will psoriasis shorten my life?
Can psoriasis be cured?
Is it true that getting a skin scrape can lead to a psoriatic lesion?
Will psoriasis cause my hair to fall out?
What should I look for in an OTC psoriasis shampoo?
Can you control psoriasis with diet?
Is Skin-Cap®
effective for controlling psoriasis?
What is parakeratosis, and what does it have to do with psoriasis?
Q. Who gets psoriasis?
A. Psoriasis occurs in both children and
adults and may appear at any age, although it is most commonly diagnosed
between the ages of 15 and 35. Both men and women of any race may be
affected.
Q. How common is psoriasis?
A. It is estimated that over seven million
Americans (2.6%) have psoriasis, with more than 150,000 new cases reported
each year. According to the National Psoriasis Foundation, 20,000 children
under 10 years of age are diagnosed with psoriasis annually.
Q. What causes psoriasis?
A. The exact cause of psoriasis is unknown;
however, researchers suspect that whether a person develops psoriasis
or not may depend on a "trigger." Possible psoriasis triggers
include emotional stress, skin injury, systemic infections,
and certain medications. Studies have also indicated that a person is
born genetically predisposed to psoriasis, and multiple genes
have been discovered over the past 5 years confirming this fact. Even
so, not everyone with psoriasis will have a family history of the disease.
Q. Is risk for skin infections higher
in people with psoriasis than in people with normal skin?
A. 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 is increased when skin and/or plaques or guttate pustules
are colonized by the highly invasive Staphylococcus aureus, a species
of bacteria capable of causing serious skin and systemic infections.
Risk for secondary infections may also be increased by hard scratching
that abrades the skin and opens it to bacterial invasion. Hard scratching
should be avoided for this reason, and also because abrasion of the
skin can be a trigger for 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 more serious, systemic infection.
Q. Is the treatment for psoriasis different for
African-Americans and other darker-skinned people than for people
with light-colored skin?
A. The immunologic dysfunctions that are a major predisposing factor
in psoriasis are believed to be the same in all persons regardless of
skin color. The patterns of genetic inheritability for the predisposing
factors may vary in different groups.
The pigmentation of skin is controlled by hormonal processes that are
unrelated to the immune and inflammatory processes that underlie psoriasis.
It is interesting to note that all humans, regardless of skin color,
have about the same number of melanocytes (pigment-containing cells)
at any given site on the skin. Variations in skin color are due to differences
in hormonal regulation of pigment formation within the melanocytes,
and transfer of the pigment from melanocytes to keratinocytes (the cells
that make up the majority of the outer layer of skin). A principal hormone
in the regulation of human skin color is melanocyte-stimulating hormone
(MSH).
The incidence of psoriasis is much lower in dark-skinned West Africans
and African-Americans than in light-skinned people of European ancestry.
Incidence is also low in Japanese and Eskimos, and is extremely low
to non-existent in Native Americans in both North and South America.
The reasons for this epidemiologic disparity are not known, but are
believed to involve genetic, geographic and environmental factors.
The treatment of psoriasis in African-Americans is largely the same
as treatment in light-skinned patients. An adjustment is therapy is
made in the use of photochemotherapy (PUVA) and phototherapy.
In PUVA, both the chemical photosensitizer and the ultraviolet dose
are adjusted for skin type and pigmentation.
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.
Q. What effect does the
sun have on psoriasis?
A. Natural sunlight can have a positive effect on
psoriasis. The long-known benefits of sunlight provided the basis for
the development of ultraviolet light therapy for treating psoriasis and
other skin diseases. However, you should never get enough sun exposure
to turn your skin red or cause a sunburn, which can actually cause
psoriasis to flare-up and worsen.
Q. Are homeopathic
treatments effective for psoriasis?
A. There is no scientific evidence that homeopathic treatments
are effective for treating psoriasis. However, it’s not impossible
that some of these treatments might be helpful. Scientific studies need
to be done in order to resolve this issue.
Q. Will psoriasis shorten
my life?
A. Psoriasis itself does not appear to shorten a
person’s life. Patients with psoriasis should be able to live full
lives into their senior years.
Q. Can psoriasis be cured?
A. No. The tendency to develop psoriasis is inherited
through a person’s genes. We hope to be able to safely modify these
genes in the future, but the technology is not yet developed. We do
foresee a time, when we will have more specific and more effective
therapies for the various forms of psoriasis. Also, while psoriasis
cannot be cured, it can often be completely cleared for periods of
months or even years. Occasionally, it never returns at all. In most
patients, however, it is a chronic, life-long condition with alternating
periods of flaring and clearing.
Q. Is it true that
getting a skin scrape can lead to a psoriatic
lesion?
A. 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). That’s 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 Koebner’s phenomenon.
Q. Will psoriasis cause my hair to fall out?
A. 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.
Q. What should I look for in an OTC psoriasis shampoo?
A. There are numerous shampoos available at most drug
stores. Look for a shampoo that contains tar or salicylic acid. Be sure
to treat your scalp gently, as harsh shampoos, scalp massages or
scratching can aggravate the disease.
Q. Can you control psoriasis with diet?
A. Unfortunately no. However, the healthier the diet
the better. Especially a diet that includes regular exercise. For more
information about exercise and psoriasis, visit the National Psoriasis
Foundation’s article archives.
Q. What is parakeratosis, and what does
it have to do with psoriasis?
A. Parakeratosis is a word you may have come across when you read
about psoriasis, especially plaque-type psoriasis. It is a term that
describes the process by which psoriatic skin continuously forms and
scales off.
In normal skin, the outer layer, made up mostly of cells called
keratinocytes, is replaced every 27 to 28 days with newly formed
keratinocytes. The replacement usually occurs without a person noticing
it; if it takes place unusually quickly or in unusual amounts, we may
notice flakes and scales on our skin, clothing, bedding, etc.
In psoriasis, the process of keratinocyte production is sped up. New
keratinocytes are formed and moved upward to the skin surface faster
than they can be incorporated into skin. Some are moved upward so fast
that they are not yet mature cells. The keratinocytes accumulate and are
scaled off. Parakeratosis is the word used to describe the entire
process.
Psoriatic plaque has other features also, including inflammatory
cells and dilated small blood vessels that contribute to both the
appearance and the symptoms of a psoriatic lesion.
In general, the cycle of psoriasis can
best be described as the body's immune system triggering excessive
skin-cell reproduction. In healthy skin, cells mature and are shed in
about 28 days. In people with psoriasis, this process is accelerated
to only 3 or 4 days. This excessive reproduction causes skin cells to
build up and form abnormal scaling seen on lesions in psoriasis.
Q. I have had psoriasis for 20 years
and my husband has been very supportive, but recently he has started to
complain about my constant scratching. He knows I need to scratch to
relieve itching, but it seems to bother him more now. I’m afraid we’re
heading for marital problems unless I can stop scratching or he can stop
letting it bother him. Any suggestions?
A. Psoriasis in a spouse can be difficult
for both marriage partners. The spouse with psoriasis not only suffers
from the disease and perhaps from problems with self-image, but also may
be acutely aware of the partner’s struggles to be supportive. Over
time, it is the ”little things” that can come between partners—for
example, flaked-off skin that must be shaken from bed sheets every
morning, or in this case the spouse’s constant scratching that becomes
a “last straw” for an otherwise supportive husband.
The husband’s growing irritation may actually
be a message worth heeding, however. While scratching is effective in
temporarily relieving pruritus (see May 2001 Update discussion
of pruritus), hard scratching can also be a trigger for formation
of new psoriatic lesions or worsening of existing lesions. Especially
during active phases of psoriasis, abrasion of the skin is one of the
causes of Koebner’s phenomenon—the induction of psoriatic lesions
by injury to the skin. Hard, constant scratching can cause the type
of skin injury that leads to development of Koebner’s phenomenon.
Since pruritus has become a major issue
for both husband and wife, the issue should be discussed with the
patient’s dermatologist. Pruritus control should perhaps be made a
focus of psoriasis treatment, along with educational counseling of both
marriage partners. As discussed in May’s Update, general measures for
control of pruritus include keeping the skin cool and moisturized and
avoiding irritating fabrics. Ice packs may help stop the itching. A
heavy moisturizing cream applied twice daily will help control scaling
and pruritus. Specific pharmacologic measures should be prescribed
by the dermatologist on the basis of the patient’s history of
psoriasis and overall medical condition.
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