The aim of this study was to evaluate the influence of selected neuropeptides on itching in psoriatic individuals. Fifty-nine patients (43 pruritic and 16 non-pruritic) with psoriasis were included in the study. The severity of psoriasis, measured using the Psoriasis Area and Severity Index scale, ranged between 2 and 43.7 points. The intensity of pruritus was evaluated using a Visual Analogue Scale. The plasma levels of substance P, vasoactive intestinal peptide, calcitonin gene-related peptide and neuropeptide Y were measured radioimmunologically. The plasma level of neuropeptide Y was significantly decreased in patients with pruritus compared with those without pruritus (21.6 +/- 39.6 pg/ml and 144.3 +/- 385.7 pg/ml, respectively; p=0.03). Levels of other neuropeptides did not differ significantly between pruritic and non-pruritic patients; however, a tendency to lower plasma levels of substance P and vasoactive intestinal peptide in patients with itching was noted. Moreover, a significant negative correlation was observed between pruritus severity and levels of substance P (r = -0.36; p=0.02), as well as between pruritus severity and plasma levels of vasoactive intestinal peptide (r = -0.34; p=0.03). The imbalance of neuropeptide activity in the sera of pruritic subjects may suggest a role for neuropeptides in perception of itching in psoriatic individuals.

Based on our results and previous literature data it could be suggested that neuropeptides may be involved in the development of psoriatic lesions.

Reference1 Veysey E, Downs AMR. Adverse side-effects following attempted removal of tattoos using a non-laser method.

Background: It is known that stress may exacerbate psoriasis. Pruritus is one of the most bothersome symptoms of psoriasis. Objective: The aim of this study was to evaluate if stress provokes itching in psoriatic subjects. Patients and Methods: 79 patients (44 males, 35 females) in an acute stage of psoriasis were included into the study. The severity of psoriasis was assessed by the Psoriasis Area and Severity Index (PASI). The psychosocial stress was measured by the Social Readjustment Rating Scale by Holmes and Rahe and by a self-assessment method. For the evaluation of itching two scales were used: a Visual Analogue Scale and a questionnaire. Results: There were significant correlations between the two scales used for pruritus evaluation (p < 0.00001) as well as between the methods employed for stress assessment (p < 0.00001). Stressful life events in the month before psoriasis exacerbation were reported by 50 patients (63.3%). Pruritus was present in 71 individuals (89.9%). Patients who experienced heavy or extremely heavy stress suffered statistically more frequently (p < 0.05) from pruritus than patients without stress. Significant correlations between the severity of stress and the intensity of itching were observed in the patients studied (p = 0.015). Conclusion: The results suggest that stress may provoke and intensify itching in psoriatic patients. Further investigations on the exact mechanism of stress effects on itching in psoriasis are required.

Background: Many patients with psoriasis suffer from itch. The pathogenesis of psoriatic itch still remains unknown. Objective: To evaluate the relationships between plasma levels of histamine, substance P (SP) and calcitonin gene-related peptide (CGRP) and the presence as well as intensity of itching among psoriatic patients. Patients and Methods: 59 psoriatic individuals (43 pruritic and 16 non-pruritic) and 32 healthy controls were included in the study. Itching was evaluated by a visual analog scale (VAS) and a specially designed questionnaire. Plasma concentrations of histamine, SP and CGRP were measured by RIA (radioimmunoassay) method. Results: The mean plasma concentration of histamine in psoriatic patients was not significantly different from that found in controls. No significant differences were found between plasma levels of histamine in the groups of psoriatic pruritic patients, non-pruritic psoriatics and controls. Also, there was no significant difference in SP plasma concentration between psoriatic individuals and controls or between pruritic, non-pruritic and healthy people. No relationships between the substances studied (histamine, SP) and intensity of pruritus could be revealed. The mean CGRP plasma level was markedly increased in patients suffering from psoriasis as compared to controls (p < 0.01). The mean CGRP concentration in the plasma of pruritic psoriatic patients was significantly higher than in controls (p < 0.01). This was not observed when comparing non-pruritic to healthy subjects. The mean concentration of CGRP in the plasma of pruritic patients was also higher than in that of non-pruritic ones, but this difference did not reach statistical significance. A significant correlation was found between itching intensity and CGRP plasma concentration in male subjects and in those patients who had been suffering from psoriasis for 5–20 years. There were, however, no correlations between CGRP level and itching intensity in the whole group of 43 psoriatic patients with pruritus. Conclusion: Circulatory CGRP could be an important factor in the pathogenesis of psoriatic pruritus, but this still needs further investigation.