Psoriasis is a chronic (long-lasting) skin disease of scaling and inflammation. The simple explanation may be it is an immune system mistake that triggers a too rapid turnover of skin cells. This in turn causes a build up skin on its surface.
Psoriasis sufferers may experience significant physical discomfort from skin itching, cracking and pain. All having the potential to interfere with basic life functions, such as self-care, walking and sleep.
Some triggers that may cause inflammation flare ups are infections, stress, and changes in climate that dry the skin and medicines, including lithium and beta blockers, which are prescribed for high blood pressure.
There are many approaches for treating psoriasis skin itching, cracking and scaling. Combining various topical, light, and systemic treatments often permits lower doses of each and can result in increased effectiveness.
So be kind to those with this unusual appearance. They are having enough difficulty living in their skin as it is.