The psoriasis area and severity index is the adequate criterion to define severity in chronic plaque-type psoriasis.
BACKGROUND
Chronic plaque-type psoriasis is a major dermatosis, but a significant question is still unanswered: What defines severity in chronic plaque-type psoriasis? While objective assessments like the Psoriasis Area and Severity Index (PASI) have frequently been used in clinical trials, quality of life (QOL) questionnaires are currently becoming more and more popular.


OBJECTIVE
This article summarizes the most important objective and subjective measurements of severity in psoriasis. For every dermatologist it is critically important to distinguish between severe psoriasis and psoriasis that severely affects QOL. Even if the PASI also has disadvantages, it is the most adequate instrument available to evaluate severity in plaque-type psoriasis.


RESULTS
We provide reasons why PASI >12 defines severe, PASI 7-12 moderate and PASI <7 mild chronic plaque-type psoriasis.
Schmitt
Jochen
J
Department of Dermatology, University Hospital Carl Gustav Carus, Technical University Dresden, DE-01307 Dresden, Germany. jm_schmitt@hotmail.com
Wozel
Gottfried
G
D006801:Humans; D011237:Predictive Value of Tests; D011565:Psoriasis / Q000473:pathology*; D012720:Severity of Illness Index