Primarily seen in adults, pustular psoriasis is characterised by white blisters of noninfectious pus (consisting of white blood cells) surrounded by red skin. There are three types of pustular psoriasis. Pustular psoriasis may be localised to certain areas of the body, such as the hands and feet, or may cover most of the body. For instance, it begins with the reddening of the skin followed by the formation of pustules and scaling. Pustular psoriasis may be triggered by an number of factors. For instance, oral medications, irritating topical agents, overexposure to UV light, pregnancy, infections, stress and sudden withdrawal of long-term medications or steroids.
Erythrodermic psoriasis is a particularly inflammatory form of psoriasis that affects most of the body surface. It may occur in association with von Zumbusch pustular psoriasis, for example. It is characterised by periodic, widespread, fiery redness of the skin and the shedding of scales in sheets, rather than smaller flakes. As a result of the reddening and shedding of the skin, there can be severe itching, increased heart rate, and fluctuating body temperature. Known triggers of erythrodermic psoriasis include the abrupt withdrawal of a systemic psoriasis treatment including cortisone, and other medications such as lithium, anti-malarial drugs; and strong coal tar products. Similarly, it can be triggered from an allergic reaction to a drug resulting in the Koebner response, from triggers like severe sunburns, infection, or stress, for example.
Nail psoriasis involves nail pitting and discolouration. Additionally, the nails are also brittle and grow abnormally. They might also be loose to a point that it detaches from the nail bed.