Last Reviewed June 2, 2009
Symptoms & Characteristics
Psoriasis is a skin disease that causes itchy or sore patches of thick, red skin with silvery scales. Patches can occur on the elbows, knees, scalp, back, face, palms and feet, but they can show up on other parts of the body as well.
Psoriasis is a long-lasting (chronic) condition. The symptoms of psoriasis come and go, but infections, stress, and dry skin can often make symptoms worse.
Treatment
Treatment for psoriasis may include topical creams, medications and light therapy.
If someone notices or experiences any of the signs or symptoms common to psoriasis, it is important to see a doctor.
How Common Is It?
Over 7 million Americans are believed to be affected with psoriasis.
Genetics & Inheritance
The cause of psoriasis is largely unknown. Psoriasis is most likely a multifactorial condition, which means it involves a combination of genetic and environmental factors.
- Some factors have been proposed to possible influence psoriasis risk. Some of these factors include severe obesity, smoking, HIV, certain medication, skin injury recurrent infections (especially strep throat), and severe stress.
It is currently well established that psoriasis runs in some families. About 33% of affected people have at least one other affected family member. Researchers believe that there are probably a number of genes that affect the development and symptoms of psoriasis.
- Researchers have identified that certain variations in multiple genes are associated with susceptibility to psoriasis in some families.
- Single nucleotide polymorphisms (SNPs) are small variations in a single "letter" of DNA that can be found throughout our entire genetic make-up. Some researchers have identified specific SNPs that may influence susceptibility to psoriasis in some people. How these SNPs contribute to psoriasis is unclear, and much of this research is considered preliminary at this point, as it is often limited to specific ethnic groups. Further research is needed to replicate study findings across different ethnic groups and clearly establish associations.
- Other yet to be identified or adequately classified genes may also contribute to psoriasis.
Genetic Testing
Clinical genetic testing for psoriasis susceptibility is currently available on a research basis only for people who are considered at risk. Use our find a genetic professional directory to locate a trained
genetic professional in your area.
Informational genetic testing for psoriasis susceptibility is available online (over the internet) as part of a whole genome scan. Whole genome scanning involves analyzing thousands of SNPs at once related to a number of different health conditions.
- At this point, many genetic professionals do not consider this testing clinically useful or medically relevant, but for informational purposes only. Go to the Tests tab to link to the
best providers, compare providers and read provider reviews.
Support & More Information
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Alternative Names
- Plaque psoriasis
- psoriasis vulgaris