[Brief review of the diagnostics of pyoderma gangraenosum].

The diagnosis of pyoderma gangraenosum was previously made as a diagnosis of exclusion. For this reason repeated attempts have been made in recent years to develop new diagnostic scores, whereby the typical clinical and anamnestic aspects were usually taken into account and the relevant differential diagnoses were excluded. With the PARACELSUS score an evaluated diagnostic score was presented for the first time. The main diagnostic criteria of this score are a rapidly progressing disease, the assessment of relevant differential diagnoses and reddish-violaceous wound borders. If these criteria are or were present 3 points are given for each criterion. Secondary criteria with a score of 2 for each of the aspects are amelioration by immunosuppressant drugs, characteristically irregular (bizarre) ulcer shape, extreme pain of >4 on a visual analog scale and localization of the lesion at the site of trauma (pathergy phenomenon). Additional criteria worth one point are suppurative inflammation in histopathology, undermined deep wound borders and the association of relevant systemic diseases. An additive score of ≥10 makes the diagnosis of pyoderma gangraenosum very likely. The newly developed and evaluated PARACELSUS score is an easy to use clinical tool to objectify securing the diagnosis of pyoderma gangraenosum.