Secondary lactose intolerance is one of the four types of lactase deficiency -- a condition in which your body can't break down the dairy sugar called lactose. Unlike primary or congenital lactase deficiency, secondary lactose intolerance is not caused by inherited genetic factors. Secondary lactose intolerance occurs as a consequence of intestinal damage following infection or chemotherapy. While lactose intolerance symptoms associated with primary, congenital or developmental lactase deficiency typically persist indefinitely following onset, symptoms of secondary lactose intolerance subside once the damaged intestinal tract heals.
Dehydration
If you have secondary lactose intolerance, you are more likely to become dehydrated than people with other types of lactase deficiency. Dehydration occurs when your body loses more water or fluid than it is able to take in. Symptoms associated with dehydration include sleepiness, increased thirst, weakness, headache and dizziness. If you become dehydrated, seek immediate medical care from your physician. In the absence of prompt medical intervention, dehydration may cause life-threatening complications.
Severe Diarrhea or Bloating
Secondary lactose intolerance typically induces severe stomach-related symptoms. These symptoms may arise within 30 minutes after you consume a dairy product. Dairy products may further irritate your intestinal tract, leading to chronic diarrhea. Diarrhea results in urgent, loose bowel movements and may also be accompanied by bloating, gas, cramping or loss of appetite. Frequent bouts of diarrhea also elevate your risk of becoming dehydrated, because you lose too much fluid through your bowel movements. Consult your medical provider if you experience diarrhea for longer than a couple of days to ensure that you receive appropriate care.
Nausea or Vomiting
After consuming milk or eating a dairy product, you may begin to feel nauseated. Severe nausea may lead to vomiting or appetite loss. Contact your doctor as soon as possible if you continue to vomit for more than 24 hours. Persistent vomiting increases your risk of dehydration, especially if it is accompanied by diarrhea. If these symptoms are bothersome, you can help limit the onset or severity of secondary lactose intolerance symptoms by avoiding milk and dairy products.
