International Rare And Severe Psoriasis Expert Network

Inclusion Criteria: * Written informed consent of the patient or legal proxy in the registry * Diagnosis of PP confirmed by a dermatologist in the participant. The type of PP can be any one of PPP, GPP/Acute Generalized Exanthematous Pustulosis (AGEP), ACH or a mixed phenotype, according to the judgment of the investigator * GPP: Primary, sterile, macroscopically visible epidermal pustules on non-acral Skin with or without systemic Inflammation; with or without plaque psoriasis; either relapsing (\>1 episode) or persistent (\>3 months) * PPP: Primary, persistent (\>3 months), sterile, macroscopically visible epidermal pustules on palms and/or soles with or without plaque psoriasis * ACH: Primary, persistent (\>3 months), sterile, macroscopically visible epidermal pustules affecting the nail apparatus with or without plaque psoriasis * At the timepoint of inclusion, the participant must have had active pustulation with either white, yellow or brown pustules within six month before baseline. Active postulation at baseline is not mandatory for inclusion. * Sufficient language skills (in the languages which the patient information and the consent form is available) for the informed consent to participate * Patients of all ancestries and skin pigment type can be included * Direct non-affected adult (\>18 years old) relatives of the participant (up to two, namely mother, father, sibling) with the purpose to provide DNA for family trio sequencing analysis. The patient is not excluded from the study if no relatives are included. Exclusion Criteria: * Any medical or psychological condition in the treating physician's opinion which may prevent the patient in registry participation for the next 5 years * Lack of informed consent for registry participation