Introduction: Psoriasis is an inflammatory skin disease. About 2 to 4 percent of population suffers from this disease especially in Scandinavian countries. It seems that psoriatic patients are susceptible to the high risk of cardiovascular diseases and diabetes mellitus (DM) so that the morbidity and mortality rates are higher in these patients. The aim of this study was to determine the relationship between psoriasis and type 2 DM. Materials and Methods: This study evaluated 80 psoriatic patients and 80 normal cases with no psoriasis, as the control group. None of the cases had DM history. FBS and glucose tolerance test with 75gr glucose were conducted on all cases of psoriatic patients and control groups. The severity of psoriasis and DM was compared to each other in both groups. On the other hand, the severity of psoriasis was evaluated in the participants. Data was analyzed in SPSS 21. Results: The mean age of the studied cases were 42.1±10.3 with an age range of 23-46. Psoriasis Vulgaris was the most prevalent type of psoriasis reported in 54 cases (67.5%). Of the studied cases, 20 psoriatic cases (25%) suffered from DM while in the control group only 4 cases (5%) had DM and this difference was significant (p=0.017). According to the analyses, the relationship between DM and years of psoriasis was significant (P=0.0001). With the accurate control of blood sugar, the intensity of psoriasis decreased significantly. Conclusion: The prevalence of type 2 DM and impaired fasting glucose (IFG) increased in psoriasis patients. Therefore, they should continuously participate in screening programs, especially in case of severe psoriasis. The mortality rate is higher in psoriasis patients comparing to others. In addition, DM and its side effects such as cardiovascular accidents may be one of the most important causes of this mortality.
