Gas and overeating are common causes of abdominal swelling, according to Healthline. Lactose intolerance and irritable bowel syndrome are common medical conditions that lead to abdominal swelling.
Lactose intolerance occurs when an individual's body cannot digest lactose, explains Healthline. As a result, the abdomen may swell due to gas and bloating. Bloating and gas are also the symptoms of irritable bowel syndrome that lead to abdominal swelling.
Ascites, a fluid buildup in the abdomen, can also cause a swollen abdomen, advises Healthline. Usually caused by liver problems, ascites swells the abdomen over time as the fluids build up. Symptoms are not generally noticeable initially. Less common causes of abdominal swelling include pancreatitis, ovarian cysts, intestine blockages, gallstones and weight gain.