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.
1 The most common form, plaque psoriasis causes dry, raised, red skin lesions (plaques) covered with silvery scales. 2  The plaques itch or may be painful and can occur anywhere on your body, including your genitals and the soft tissue inside your mouth.3  You may have just a few plaques or many. 4  Nail psoriasis. The most common form, plaque psoriasis causes dry, raised, red skin lesions (plaques) covered with silvery scales. 2  The plaques itch or may be painful and can occur anywhere on your body, including your genitals and the soft tissue inside your mouth.