This study aimed to highlight the importance of routine screening for hyperglycemia and to develop a standardized, evidence-based approach for the management of pemphigus patients on prolonged systemic corticosteroid (CS) therapy. A cross-sectional study was conducted in two university-affiliated teaching hospitals using a referred sample of 200 patients with a confirmed diagnosis of pemphigus vulgaris, pemphigus foliaceus, or mucous membrane pemphigoid. All patients were receiving systemic CS therapy. A total of 150 patients responded to the survey. Six participants were excluded and 144 were included. The main outcome measure was blood glucose level to detect hyperglycemia. New-onset hyperglycemia was identified in 40% of patients who received CS therapy. None of the expected variables, including age, body mass index, family history of diabetes, corticosteroid dose, and duration of corticosteroid therapy, were independently associated with new-onset hyperglycemia. These findings indicate that the prevalence of CS-induced hyperglycemia in pemphigus patients is 40% and that in patients with pemphigus or MMP, CS therapy is associated with a markedly increased risk for hyperglycemia (odds ratio = 10.7, 95% confidence interval 1.38-83.50) compared with that of patients with the same diseases who do not receive CS therapy.