Psoriasis can have a pustular feature. When it is associated with a pyoderma gangrenosum, it leads to a nosologic problem. Is it the same entity, neutrophilic dermatosis with different clinical manifestations? Here we report the first clinical case of pustular psoriasis of the face associated with perianal pyoderma gangrenosum. This case comes out with these rare locations of the two diseases, responsible for unclear diagnosis. We highlight the importance of biological examinations, to eliminated the others diseases and the key role of histopatholigical examination into the positive diagnosis. It doesn't to be save up in our context and it have to be done when the treatment failed. The follow up of these two diseases was successful under corticosteroid therapy.