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.
These include: 1  Plaque psoriasis. 2  The most common form, plaque psoriasis causes dry, raised, red skin lesions (plaques) covered with silvery scales. 3  The plaques itch or may be painful and can occur anywhere on your body, including your genitals and the soft tissue inside your mouth. Severe cases may cause the nail to crumble. 2  Scalp psoriasis. 3  Psoriasis on the scalp appears as red, itchy areas with silvery-white scales. 4  The red or scaly areas often extend beyond the hairline. 5  You may notice flakes of dead skin in your hair or on your shoulders, especially after scratching your scalp.