A decade-long sour-taste sensation successfully treated with a proton-pump inhibitor

We report a case study of a 54-year-old Japanese woman who persistently suffered from a sour-taste sensation in her mouth for 10 years, and was treated with a proton-pump inhibitor (PPI). She found sour-tasting meals irritable, and after eating such meals the sour-taste sensation worsened. She also complained of eructation and regurgitation. Upper gastrointestinal (GI) endoscopy showed duodenal erosion, superficial gastritis, and erosive oesophagitis. After 2 weeks of PPI therapy (lansoprazole, 30 mg day(-1)) the sour taste subjectively decreased to 70%, and after 6 weeks the symptoms disappeared. In addition to increased sensitivity of the mouth, gastro-oesophageal reflux might have created her obstinate sour-taste sensations. It is suggested that in such cases PPI therapy should be attempted.