The clinical picture with acute gastritis is characterized by a diffuse pressure that can increase to intense pain in the stomach region. Eating intensifies the pain. Vomiting often brings relief. The complaints resolve over a few hours to days. The stomach symptoms are frequently accompanied by intestinal manifestations (meteorism, diarrhea).

Erosive gastritis is an important cause of hematemesis.

Causes. Apart from infections (primarily Helicobacter pylori, very rarely other bacterial [phlegmonous, mycobacterial, luetic gastritis], viral [herpes simplex virus, cytomegalovirus; particularly with AIDS], parasitic or fungal causes), the causes of acute gastritis are: food poisoning (Staphylococcus aureus toxin), alcohol, stress (surgery, serious trauma, shock) and in particular drugs, primarily nonsteroidal antirheumatics (e. g., salicylates, phenylbutazone, indomethacin), corticosteroids, and cytostatic drugs.

Differential Diagnosis. Gastritis is often interpreted as primary, although it is frequently an expression of a more general disease. The following diseases present with gastric complaints and must always be considered in differential diagnosis:
➤ Any serious general disease can show symptoms indicating a stomach disease, such as nausea, belching, loss of appetite, and possibly vomiting.
➤ These symptoms are particularly frequent in chronic uremia.
➤ Acute or chronic liver diseases (e. g., due to chronic alcohol abuse) are frequently accompanied by gastric complaints.
➤ Congestive gastritis, as a manifestation of cardiac insufficiency or portal hypertension, must be considered in patients with cardiac or hepatic disease.
➤ Among drugs, “digitalis gastritis” in cardiac patients disappears a few days after stopping therapy.
➤ Allergic gastritis, as a consequence of hypersensitive reactions to food, particularly milk, chocolate, yeast, nuts, citrus fruit, strawberries, shellfish, etc., occurs primarily as part of a generalized gastrointestinal reaction with diarrhea and pain, in some cases combined with systemic symptoms (e. g., tachycardia, drop in blood pressure, asthma, headache, urticaria).