Aim 1: Harmonized phenotyping:
Harmonization of diagnostic criteria for pustular psoriasis and position paper. Finalization of electronic adaptable case report form, starting collection of clinical information of pustular psoriasis cases, phenotype quality control, paper on clinical data of the first  ~150 cases.

Aim 2: Web platform with underlying database:
Integration of electronic case report form with available secure database, starting real-time publication of statistics on treatments used and clinical efficacy data.

Aim 3: Virtual biobank
Submission of matching study protocols adapted for each country, distribution of DNA (saliva) sample collection tubes, start of sample collection, linking of samples with clinical data in secure database, first collaborative project on genetic architecture of palmoplantar pustulosis with ~150 samples pooled from all over Europe.