Insulin resistance, diabetes mellitus and thyroid dysfunction in patients with palmoplantar pustulosis: a case-controlled study

INTRODUCTION Palmoplantar pustulosis (PPP) is a chronic pustular inflammatory skin disease; however, its pathogenesis is not well understood. Several factors, such as genetics, tobacco use and autoimmune issues, may contribute to this disease. AIM This research was conducted to investigate the relationships between insulin resistance, thyroid disease and PPP. MATERIAL AND METHODS Thirty-three patients with PPP and 27 age- and gender-matched controls were analysed for their smoking histories, thyroid function tests, anti-thyroid peroxidase antibody (anti-TPO) levels, fasting glucose, fasting insulin levels and the homeostatic model assessment (HOMA) index for insulin resistance. RESULTS We found significant differences between the PPP and control groups according to their tobacco use and anti-TPO levels (p = 0.009 and p = 0.009, respectively). The proportion of tobacco use was 90% in the PPP patients and 63% in the controls. Gender and tobacco use were predictive risk factors for PPP in the multivariate analysis (OR = 141.7, p < 0.0001 and OR = 147.6, p = 0.006, respectively). An anti-TPO level > 35 U/ml and the presence of a thyroid abnormality were independent risk factors in the univariate, but not the multivariate analysis (OR = 4.2, p = 0.025 and OR = 5.4, p = 0.004, respectively). A moderate correlation between the gender and anti-TPO level was found (r = 0.361, p = 0.039); however, the fasting glucose, insulin and HOMA index were not significant between the PPP and control groups. CONCLUSIONS Female gender and smoking were the most important risk factors for PPP; however, the increase in the anti-TPO level may be related to the predominance of females afflicted with this disease. Additional studies are necessary to clarify the relationships between PPP, thyroid disease and diabetes mellitus.