[Pruritus in psoriasis : Profile and therapy]

Introduction of a Specific Dermatological Rehabilitation Programme for Patients with Chronic Pruritus: A Pilot Study

Chronic pruritus is a common symptom, associated with several severe medical conditions, great psychological burden, and reduced quality of life. It also poses socio-economic challenges concerning patients' work loss and healthcare costs. In Germany, medical rehabilitation programmes represent an integral part of the medical care of patients with chronic inflammatory skin diseases. However, such programmes play only a rudimentary role in the treatment of other dermatological diseases, such as dermatological oncology, genetic skin diseases, and chronic pruritus. Therefore, a specific antipruritic dermatological rehabilitation programme was developed in cooperation between the Department of Dermatology of the Medical Rehabilitation Center Bad Bentheim and the Center for Chronic Pruritus of the University Hospital of Muenster, Germany. This prospective study compared short-term patient-reported outcomes (n = 121) at the beginning and end of the rehabilitation programme. The majority of subjects had chronic pruritus on primary diseased, inflamed skin. Significant improvements in pruritus intensity (p ≤ 0.001), quality of life (p ≤ 0.001), anxiety symptoms (p ≤ 0.001) and depression (p ≤ 0.001), as well as an overall patient-relevant benefit (Patient Benefit Index 2.6 ± 1.06) and treatment-related patients' satisfaction, were shown. This suggests that implementation of this standardized rehabilitation programme for treatment of patients with chronic pruritus was successful.

Transcriptional Analysis-Based Alterations Affecting Neuritogenesis of the Peripheral Nervous System in Psoriasis

An increasing amount of evidence indicates the critical role of the cutaneous nervous system in the initiation and maintenance of psoriatic skin lesions by neurogenic inflammation. However, molecular mechanisms affecting cutaneous neurons are largely uncharacterized. Therefore, we reanalyzed a psoriatic RNA sequencing dataset from published transcriptome experiments of nearly 300 individuals. Using the Ingenuity Pathway Analysis software, we associated several hundreds of differentially expressed transcripts (DETs) to nervous system development and functions. Since neuronal projections were previously reported to be affected in psoriasis, we performed an in-depth analysis of neurite formation-related process. Our in silico analysis suggests that SEMA-PLXN and ROBO-DCC-UNC5 regulating axonal growth and repulsion are differentially affected in non-lesional and lesional skin samples. We identified opposing expressional alterations in secreted ligands for axonal guidance signaling (RTN4/NOGOA, NTNs, SEMAs, SLITs) and non-conventional axon guidance regulating ligands, including WNT5A and their receptors, modulating axon formation. These differences in neuritogenesis may explain the abnormal cutaneous nerve filament formation described in psoriatic skin. The processes also influence T-cell activation and infiltration, thus highlighting an additional angle of the crosstalk between the cutaneous nervous system and the immune responses in psoriasis pathogenesis, in addition to the known neurogenic pro-inflammatory mediators.

Effect of narrowband ultraviolet B therapy on serum levels of CD26/dipeptidyl-peptidase IV and truncated forms of substance P in psoriasis patients with pruritus

Purpose

While pruritus affects approximately 60–90% of psoriasis patients, the pathogenesis of the condition remains unclear. CD26/dipeptidyl-peptidase IV (CD26/DPPIV) and truncated forms of substance P (SP) have been reported to play an important role in the pathogenesis of psoriatic itch. The aim of this study was to determine the serum levels of soluble CD26/DPPIV and truncated forms of SP in response to narrowband ultraviolet B (NBUVB) therapy.

Patients and methods

The peripheral blood of 13 participants with moderate to severe psoriasis (psoriasis area and severity index (PASI) ≥10) who presented with pruritus symptoms and 12 psoriasis-free participants were collected. Seven of the 13 patients agreed to be treated with NBUVB. The PASI was evaluated. Additionally, the clinical assessment of itch was performed with the visual analog scale (VAS) and the itch severity scale (ISS).

Results

The results showed that the levels of truncated SP were significantly higher in participants with psoriasis compared to participants without psoriasis. (302.20±56.87 vs 234.96±78.01 pg/ml, p<0.05). After irradiation, truncated SP significantly decreased from 288.85±66.22 pg/ml to 252.13±49.78 pg/ml, p<0.05. The CD26/DPPIV levels were lower in psoriasis participants compared to the healthy participants (526.34±145.35 vs 593.19±84.92 ng/ml, p>0.05) and increased significantly after NBUVB therapy (518.13±173.0 ng/ml to 592.7±193.9 ng/ml, p<0.05). NBUVB therapy caused alterations to the serum levels of truncated SP and CD26/DPPIV.

Conclusion

The decreased serum levels of truncated SP and increased levels of CD26/DPPIV post-NBUVB treatment observed in this study provides insight into the underlying molecular mechanisms of the treatment; this may be used in the prospective monitoring and development of improved psoriasis-related pruritus therapeutics. Further studies, comprising a larger cohort, are required to confirm these results.