Immediate manifestations of caustic substance ingestions include erosions of mucosal surfaces of the gastrointestinal tract or airway (which can cause bleeding if the erosions extend to a blood vessel), mouth and tongue swelling, drooling or hypersalivation, nausea, vomiting, dyspnea, dysphonia/aphonia irritation of the eyes and skin. Perforation of the esophagus can lead to mediastinitis or perforation of the stomach or bowel can lead to peritonitis Swelling of the airway or laryngospasm can occur leading to compromised breathing. Injuries affecting the respiratory system include aspiration pneumonia and laryngeal sores. Signs of respiratory compromise include stridor and a change in a person's voice.
Later manifestations of caustic substance ingestions include esophageal strictures or stenosis; which can result in chronic pain and malnutrition. Esophageal strictures more commonly occur after more severe mucosal injury, occurring in to 71% and 100% of grade 2b and 3 mucosal lesions respectively. Remote manifestations of caustic ingestions include esophageal cancer. People who have a history of caustic substance ingestion are 1000-3000 times more likely to develop esophageal cancer with most cases occurring 10–30 years after the ingestion.