noun. 1  a. A cylindrical, usually metal casing containing the primer and charge of ammunition for firearms. 2  A case filled with high explosives, used in blasting. 3  A small modular unit designed to be inserted into a larger piece of equipment: an ink cartridge; a disposable cartridge of caulking compound. A removable case containing the stylus and electric conversion circuitry in a phonograph pickup.
Guttate psoriasis causes a rash formed of drop-shaped salmon-pink areas on the chest, arms, legs and scalp. Guttate psoriasis. Red drop-like lesions are found on the skin. Image courtesy of Dr Hon Pak.
At this time, it is not known what causes plaque psoriasis. What experts do know is there's a link between the immune system, genetics and plaque psoriasis. The majority of researchers conclude that with plaque psoriasis, the immune system is triggered in error.t this time, it is not known what causes plaque psoriasis. What experts do know is there's a link between the immune system, genetics and plaque psoriasis. The majority of researchers conclude that with plaque psoriasis, the immune system is triggered in error.