Platelet-related parameters as systemic markers of erythrodermic psoriasis.

Erythrodermic psoriasis (EP) is a severe disease with systemic inflammation and complications. The pathogenesis remains largely unknown. Recent studies have shown that platelets play important roles in psoriasis, but the association between platelets and EP is unclear. This study aimed to analyse, for the first time, the clinical significance of platelet-related parameters in EP patients. We retrospectively investigated the clinical and laboratory data of 92 EP patients, 93 sex/age-matched psoriasis vulgaris (PsV) patients, and 93 matched healthy controls (HC). The platelet-related parameters, including platelet count, plateletcrit (PCT), mean platelet volume (MPV), platelet distribution width (PDW), platelet large cell ratio (P-LCR) and platelet/lymphocyte ratio (PLR), were compared between the three groups. Associations between these parameters and disease severity, and between platelet count and complications of EP were analysed, and compared before and after treatment. Platelet count, PCT, and PLR were significantly elevated in EP compared with PsV and HC (p < 0.001). MPV was higher in EP patients compared with HC (p < 0.001). Based on ROC analyses, moderate-to-severe and mild EP could be clearly distinguished based on platelet count and PCT. In terms of complications, a platelet count level ≥ 270 × 109/L was associated with a significantly higher rate of hypoalbuminemia and abnormal liver function. After treatment, platelet count, PCT, and PLR were significantly reduced. Our data show, for the first time, a significant alteration of platelet-related parameters in EP patients, indicating a strong association between platelets and EP. Platelet count and PCT may be used as cost-effective and simple tools to serve as systemic markers for EP.