Definition

• Tongue red & smooth

• Nutritional deficiency, eg, niacin (pellagra), riboflavin, pyridoxine, vitamin B₁₂, folate, iron, vitamin E
• Drug reaction
• Dehydration
• Irritants
• Pernicious anemia
• Psoriasis
• Glucagonoma
• Median rhomboid glossitis

• Glossodynia
• Dry mouth