Research indicates that the disease may result from a disorder in the
immune system. The immune system makes white blood cells that protect
the body from infection. In psoriasis, the T cells (a type of white
blood cell) abnormally trigger inflammation in the skin. These T cells
also cause skin cells to grow faster than normal and to pile up in raised
patches on the outer surface of the skin.
Those with a family history of psoriasis have an increased chance of
having the disease. Some people carry genes that make them more likely
to develop psoriasis. When both parents have psoriasis, the child may
have a 50% chance of developing psoriasis. About one third of those
with psoriasis have at least one family member with the disease.
Certain factors may trigger psoriasis.
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Injury to the skin: Injury to the skin has been
associated with plaque psoriasis. For example, a skin infection, skin
inflammation, or even excessive scratching can trigger psoriasis.
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Sunlight: Most people generally consider sunlight
to be beneficial for their psoriasis. However, a small minority find
that strong sunlight aggravates their symptoms. A bad sunburn may
worsen psoriasis.
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Streptococcal infections: Some evidence suggests
that streptococcal infections may cause a type of plaque psoriasis.
These bacterial infections have been shown to cause guttate psoriasis,
a type of psoriasis that looks like small red drops on the skin.
Guttate psoriasis. Red drop-like lesions are found on
the skin. This type of psoriasis usually occurs after a streptococcal
(bacterial) infection. Image courtesy of Hon Pak, MD.
HIV: Psoriasis typically worsens after an individual
has been infected with HIV. However, psoriasis often becomes less active
in advanced HIV infection. Drugs: A number of medications have been shown to aggravate psoriasis.
Some examples are as follows:
Lithium – Drug that may be used to treat depression Beta-blockers – Drugs that may be used to treat high blood pressure Antimalarials – Drugs used to treat malaria NSAIDs – Drugs, such as ibuprofen (Motrin and Advil) or naproxen
(Aleve), used to reduce inflammation Emotional stress: Many people see an increase in their psoriasis
when emotional stress is increased. Smoking: Cigarette smokers have an increased risk of chronic plaque
psoriasis. Alcohol: Alcohol is considered a risk factor for psoriasis, particularly
in young to middle-aged males. Hormone changes: The severity of psoriasis may fluctuate with
hormonal changes. Disease frequency peaks during puberty and menopause.
A pregnant woman’s symptoms are more likely to improve than worsen,
if any changes occur at all. In contrast, symptoms are more likely to
flare in the postpartum period, if any changes occur at all.
Risk factors
Perhaps the most significant risk factor for psoriasis is having a family
history of the disease. About one in three people with psoriasis has a
close relative who also has the condition. On the other hand, roughly
the same proportion of people carries genes that have been linked to psoriasis
yet never develop skin problems, indicating just how complex and perplexing
psoriasis is.
Other psoriasis risk factors include:
Other medical conditions. People with HIV are more likely to develop
psoriasis than people with healthy immune systems are. Children and
young adults with recurring infections, particularly strep throat, also
may be at increased risk. -
Stress. Because stress can have a strong impact on your immune system,
high stress levels may increase your risk of psoriasis.
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Obesity. Excess weight increases your risk of inverse psoriasis.
In addition, plaques associated with all types of psoriasis often develop
in skin creases and folds.
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Smoking. Smoking tobacco not only increases your risk of psoriasis
but also may increase the severity of the disease. Smoking may also
play a role in the initial development of the disease.,/p>
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