Quantification of Histopathological Changes in Patients With Psoriasis Before and After Phototherapy

Photodermatol Photoimmunol Photomed. 2019 Sep;35(5):354-359. doi: 10.1111/phpp.12492. Epub 2019 Jun 26.


Background: One of the most used resources for the treatment of psoriasis is ultraviolet radiation (UV) with psoralens (PUVA) and narrow-band UV (UVB-NB 311-312 nm). Although many researchers have assessed the histopathological effects of this therapy modality, none used a morphological classification system specific to psoriasis.

Purpose: To assess the clinical and histopathological response in the phototherapy treatment of plaque psoriasis with PUVA and UVB-NB with use of PASI and TROZAK.

Methods: Histopathological changes of plaque psoriasis were quantified with help of the grading system for psoriasis-Trozak in 20 patients of both sexes, before and after 32 PUVA phototherapy sessions (10 patients-GPUVA) and UVB-NB (10 patients-GUVB-NB). The severity and extension of psoriasis was evaluated through PASI. The slides stained with hematoxylin and eosin were scanned in an Aperio CS2 scanner (Leica Biosystems) and evaluated through the software ImageScopeTM (Aperio Technologies). Statistical analysis was performed with the use of the program SPSS 22.0, with application of the Wilcoxon and Mann-Whitney tests.

Results: All patients presented improvement in psoriatic plaques with decrease in PASI after treatment (P < 0.01) and significant reduction in histopathological changes in psoriasis from 15.4 ± 1.7 to 3.7 ± 3.2 (P < 0.01) in group GPUVA and from 13.2 ± 1.7 to 4.9 ± 5.2 (P < 0,01) in group GUVB-NB.

Conclusions: Phototherapy, regardless of type, is an effective treatment for moderate and severe psoriasis, with possibility of being quantified clinically by PASI and histopathologically by Trozak.

Keywords: PASI; histopathology; phototherapy; psoriasis.

MeSH terms

  • Adolescent
  • Adult
  • Female
  • Humans
  • Male
  • Middle Aged
  • PUVA Therapy*
  • Psoriasis / drug therapy*
  • Psoriasis / pathology*
  • Skin / pathology*