Generalized pustular psoriasis (GPP) is an extremely rare type of psoriasis that can present in a variety of forms. Unlike the most general and common forms of psoriasis, GPP usually covers the entire body and with pus-filled blisters rather than plaques. GPP can present at any age, but is rarer in young children. It can appear with or without previous psoriasis conditions or history, and can reoccur in periodic episodes. Signs and symptoms
GPP presents as pustules and plaques over a wide area of the body. It differs from the localized form of pustular psoriasis in that patients are often febrile and systemically ill.However, the most prominent symptom, as described in the Archives of Dermatology, is "sheeted, pinhead-sized, sterile, sub-corneal pustules". The IPC roundtable adds that these pustules often occur either at the edges "of expanding, intensely inflammatory plaques" or "within erythrodermic skin". Causes
Most cases of generalized pustular psoriasis present in patients with existing or prior psoriasis conditions. However, there are many cases of GPP that arise without a history of psoriasis.The Department of Dermatology of the University of São Paulo proposed a classification for these two conditions. Pso+ represents patients with a personal history of psoriasis and pso- represents patients with no history of psoriasis. They also identified a common factor among patients in each group: In the pso+ group, the most common precipitating factor is corticosteroid withdrawal. In the pso- group, the most common precipitating factor is infection.In a large portion of cases, the disease is brought on by some triggering factor.
The trait is now extinct and was never fully characterized.Diplopodia-3
This is an autosomal trait that may be the least severe of the five. Diplopodia-4
This sex-linked mutation is similar to the previous mutations, but causes the embryo to grow thicker wing bones.Diplopodia-5
This is an autosomal mutation that gives embryos webbing between the inner two front toes on each foot, in addition to the usual characteristics of diplopodia. Almost all of the embryos survive to the end of incubation, but they are unable to clear the fluid from their lungs or absorb the blood from their extraembryonic vessels. These problems always prevent them from hatching. Almost all diplopodia-5 embryos have only one or two extra toes on each foot, so this mutation causes the least extreme foot malformation. See also
Limb development
Congenital abnormality
Dysmelia
Sonic hedgehog
Polydactyly


== References ==