Reflux oesophagitis: what acid does to the squamous lining
- Lesion
When stomach acid repeatedly flows back up, the lining of the lower oesophagus thickens, gets inflamed and may erode.
What it is
Gastro-oesophageal reflux is the commonest cause of oesophagitis. Transient relaxations of the lower oesophageal sphincter, mediated by the vagus and triggered by gastric distension, let acid and pepsin (sometimes bile) bathe the squamous epithelium. The epithelium responds by proliferating and recruiting inflammatory cells, and in some patients it erodes, scars or changes into columnar (Barrett) mucosa.
Structure
- Endoscopy: hyperaemia, then linear erosions above the junction.
- Basal zone (proliferative) layer expanded beyond its normal share of the epithelium.
- Lamina propria papillae reaching up toward the surface.
- Scattered intraepithelial eosinophils; neutrophils and erosions in severe cases.
Step by step
- The lower sphincter relaxes transiently or is weak, or a hiatal hernia removes the crural pinch.
- Acid and pepsin flow back onto squamous epithelium.
- Surface cells are injured and shed; basal cells proliferate to replace them.
- Inflammatory cells (eosinophils, then neutrophils) enter the epithelium.
- Repeated injury leads to erosion, fibrotic stricture or columnar metaplasia.
Clinical notes
- Sliding hiatal hernias (junction pulled into the chest) are common and favour reflux; paraoesophageal hernias can strangulate.
- Endoscopy is kept for symptoms that resist acid suppression or for suspected complications.
Test yourself
Think of the answer, then tap the question to see it.
What is thought to be the main mechanism of gastro-oesophageal reflux?
Transient, vagally mediated relaxation of the lower oesophageal sphincter, often triggered by gastric distension.
What are three histological features of reflux oesophagitis?
Basal zone hyperplasia, elongated lamina propria papillae and intraepithelial eosinophils (neutrophils in severe cases).
Which long-term change of reflux carries a cancer risk?
Barrett oesophagus, intestinal-type columnar metaplasia that can progress to adenocarcinoma.
Elsewhere in DurgiPedia
Connections
Educational content on the mechanisms of disease; not a diagnostic or treatment guide and no substitute for a health professional's advice. No doses are given.
Sources: Gastroesophageal Reflux Disease (GERD) (StatPearls (NCBI Bookshelf), 2025); Esophagitis: MedlinePlus Medical Encyclopedia (MedlinePlus, US National Library of Medicine, 2025).
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Representative model, for educational purposes only.