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By Mayo Clinic staffGiardia infection is almost never fatal in industrialized countries, but it can cause lingering symptoms and serious complications, especially in infants and children under 5. The most common complications include:
- Dehydration. Often a result of severe diarrhea, dehydration occurs when the body doesn't have enough water to carry out its normal functions.
- Failure to thrive. Chronic diarrhea from giardia infection can lead to malnutrition and harm children's physical and mental development.
- Lactose intolerance. Many people with giardia infection develop lactose intolerance — the inability to properly digest milk sugar. The problem may persist long after the infection has cleared, leading to malabsorption and weight loss in some.
- Skin rash. In rare cases, giardia infection may cause a skin rash or hives.