Glossary of terms: V

inflammation of blood vessels, a feature of some rheumatic diseases but not psoriatic arthritis

is a microscopic particle that can infect the cells of a biological organism. Viruses can replicate themselves only by infecting a host cell. They therefore cannot reproduce on their own.

should not be confused with vitamin tablets or liquids that you may take as dietary supplements. Whilst their chemical structure may be based on a vitamin D3 molecule they have been modified to have a completely different effect.

light coloured blotches which appear on the skin or hair as a result of the absence of the pigment melanin, the presence of which gives the skin its colour.

is latin for common and used for the most widespread plaque version, called psoriasis vulgaris.