Introduction: Unilateral and bilateral tongue cyanosis usually occurs due to the Raynaud syndrome and in the underlying severe types of vasculitis and rheumatology.
Case Presentation: The present study was conducted on a 54-year-old woman who referred to the emergency department with complaints of sudden and painless discoloration of the left half of the tongue. The patient had no history of disease other than diabetes controlled with glibenclamide. Clinical examination of the head and neck revealed evidence of unilateral cyanosis in the left half of the tongue without pain, whose discoloration did not improve with warming of the tongue.
Conclusion: Cyanosis in the emergency department can be managed appropriately by considering some parameters including history taking, history of cyanosis occurrence, history of cardiopulmonary disease, cold sensitivity and history of rheumatologic diseases, presence or absence of nail clubbing, arterial blood oxygen saturation and arterial blood gas test results. These parameters can be effective in designing a treatment regimen, while differentiating the causes of central from peripheral cyanosis.