Principal Determinants of the Length of Remission of Psoriasis Vulgaris After Topical, NB-UVB, and PUVA Therapy

Abstract

Periods of remission and of exacerbation of psoriatic lesions are common in psoriasis. We recently reported C-reactive protein (CRP) as a marker of psoriasis severity and that some patients still presented with a residual inflammation after treatment. We wondered if this residual inflammation could underlie an earlier exacerbation of psoriasis. The purpose of our study was to evaluate if there is a relationship between CRP levels, Psoriasis Area and Severity Index (PASI), and body mass index (BMI), at the end of psoriasis treatment, with the length of psoriasis remission. We followed 46 patients studied at the end of treatment, to record the length of remission; 9 of the patients were treated with topical agents, 17 with narrow-band UVB (NB-UVB), and 20 with psoralen plus UVA (PUVA). We found that the length of remission correlated with the values for PASI and CRP at the end of therapy. By performing a multiple linear regression analysis, CRP, PASI, and BMI were each significantly associated with length of remission. Patients with residual inflammation at the end of treatment presented with a significantly shorter length of remission. When considering patients grouped according to the used therapies, CRP and PASI also emerged as potential determinants of length of remission, especially in the case of patients treated with NB-UVB and topical therapy. Our data suggest that CRP and PASI are important determinants of length of psoriasis remission for patients treated with phototherapy or topical therapy. Further studies with larger groups of patients are warranted to test this hypothesis. Moreover, we propose that, by the end of the treatment, the evaluation of CRP and PASI could be important to decide, when possible, if the treatment should be continued to achieve lower CRP values and longer periods of remission.