Low serum testosterone levels in male psoriasis patients correlate with disease severity

Psoriasis is a chronic inflammatory skin disease with a genetic and autoimmune background. The involvement of sex hormones as a trigger factor for psoriasis has been suspected. Recently, low serum testosterone has been associated with autoimmune diseases in males, and the role of testosterone in psoriasis is unknown. To investigate serum testosterone levels in male psoriasis patients compared to control individuals with regards to the severity of psoriasis. A total of 121 male psoriasis patients and 217 control individuals were enrolled. The severity of psoriasis was documented using the Psoriasis Area Severity Index (PASI). Serum testosterone, sex hormone binding globulin (SHBG), and albumin were analysed. Moreover, psoriasis medication and the incidence of metabolic syndrome were recorded. In 52.1% psoriasis patients, low total testosterone values were detected. Compared to the control cohort, total testosterone (tT) and free testosterone (fT) in psoriasis patients were significantly lower. Despite psoriasis-specific medication, there was a significant inverse correlation between tT or fT and PASI, irrespective of age above or below 40 years. Low tT levels also correlated with the prevalence of metabolic syndrome. Nevertheless, in psoriasis patients without metabolic syndrome, higher PASI (≥10) was associated with significantly lower tT values. In addition, low tT was associated with clinical symptoms of testosterone deficiency. Severe psoriasis is associated with low serum testosterone. However, further studies are required to investigate whether this observation is an epiphenomenon and whether testosterone substitution might decrease the severity of psoriasis.