title: Histopathological findings are associated with the clinical types of psoriasis but not with the corresponding lesional psoriasis severity index.
abstract: BACKGROUND
  The assessment of the severity of psoriasis is often subjective because of the lack of quantitative laboratory diagnostic tools. Histopathological examination is the most commonly performed procedure for psoriasis diagnosis; however, it is usually descriptive. Thus, there is currently no quantitative method of determining psoriasis severity. The clinical types of psoriasis are correlated with the severity of the disease, and a lesional severity index, such as the psoriasis severity index (PSI), could be used as a quantitative tool for assessing gross severity.
  
  
  OBJECTIVE
  To correlate the histopathological findings of psoriasis with the PSI.
  
  
  METHODS
  Psoriatic lesions in 98 patients were evaluated. The lesions were classified into the guttate, papular, small plaque, and large plaque types according to morphology, and were scored according to the PSI. Ten common histopathological features of psoriasis were evaluated for correlation with gross severity.
  
  
  RESULTS
  The clinical types of psoriasis showed significant correlations with the histopathological severity. However, the PSI score showed no correlation with histopathological severity.
  
  
  CONCLUSIONS
  In the future, subjective gross assessment should be modified by using objective measuring devices with detailed scales, in order to correlate the findings with the histological severity.
authors: Department of Dermatology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors: Byung Yoon
authors: BY
authors: Kim
authors: Department of Dermatology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors: Jae Woo
authors: JW
authors: Choi
authors: Department of Dermatology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors: Bo Ri
authors: BR
authors: Kim
authors: Department of Dermatology, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea.
authors: Sang Woong
authors: SW
authors: Youn
keywords: Adult; Classification; Evidence-based practice; Pathology; Psoriasis