“A family came to see me after their 11-year-old daughter had been suffering from stomach pains, loss of appetite and nausea for months. She wasn’t attending school, and all gastrointestinal tests came back normal. The family tried to change her diet, gave her probiotics, and even took her to therapy because they were told it might just be stress.
But when we examined him more closely, we noticed something more serious. In addition to his stomach problems, he was unusually tired, had difficulty concentrating, and had recently developed knee pain. His symptoms fit a pattern I had seen before, especially in children with Lyme disease.
After we began treating Lyme disease and co-infections, his stomach problems improved, and he returned to school with energy and confidence.
Gastrointestinal symptoms are extremely common in Lyme disease, yet they are often misunderstood, overlooked, or treated in isolation. For many people, however, the gut is one of the first systems affected by Lyme disease or co-infections. By paying attention to these signs, we can often recognise the disease earlier and treat it more effectively.
How does Lyme disease cause gut symptoms?
Lyme disease does not only affect the joints or the brain. It can also affect the body’s digestive processes.
This is partly because the autonomic nervous system, which regulates things like bowel movements and blood flow after eating, can be disrupted by infection. When these signals are thrown out of balance, an individual may experience nausea, bloating, feeling full after just a few bites, or even fatigue after eating. For some people, these changes occur before the more familiar symptoms of Lyme disease.
In fact, a study of 314 patients with early-stage Lyme disease found that 23% reported loss of appetite, 17% reported nausea, and 10% reported vomiting—clear evidence that the gut is often affected from the outset.
The immune system also plays a role. Inflammation caused by Lyme disease or a co-infection can affect digestion, increase intestinal sensitivity, or change the way the body processes food.
The pitfalls of testing: Why doesn’t a normal result always mean that everything is fine?
Many of my patients undergo gastrointestinal tests – endoscopy, colonoscopy, abdominal imaging – with normal results. But normal test results do not mean normal function. Lyme disease and its co-infections often disrupt motility and nerve signal transmission in ways that standard tests cannot detect.
7 intestinal signs that may indicate Lyme disease
If you experience any of these symptoms or other signs of tick-borne disease—such as fatigue, brain fog, or joint pain—your intestinal problems may indicate Lyme disease or a co-infection.
- Persistent nausea despite normal lab results and imaging tests
- Early satiety – feeling full after just a few bites
- Bloating that cannot be explained by diet or IBS
- Alternating constipation and diarrhoea
- Heartburn or reflux that does not improve with medication
- Abdominal cramps or pain despite normal GI tests
- Fatigue or dizziness after eating, especially in patients with POTS
Special note on paediatric cases
In children, intestinal symptoms associated with Lyme disease may manifest as loss of appetite or stomach ache at school. Sometimes these are mistakenly attributed to anxiety. But these symptoms should be taken seriously—especially if they are accompanied by behavioural changes, fatigue, or joint pain.
Gastrointestinal symptoms can mimic other diseases
Gastrointestinal symptoms of Lyme disease can mimic the following:
- Functional dyspepsia
- Irritable bowel syndrome (IBS)
- Gastroparesis
- Mast cell activation syndrome (MCAS)
- Small intestinal bacterial overgrowth (SIBO)
If you have been diagnosed with one of these conditions but treatments have not helped, it is worth considering the possibility of Lyme disease or a co-infection.
Why do gut symptoms deserve more than a referral to a gastroenterologist?
Too often, patients are sent to a gastroenterologist, where they are diagnosed with IBS, functional dyspepsia or reflux without further investigation. In the case of Lyme disease, these diagnoses are not always helpful and certainly do not explain why digestion has changed.
If we ignore the intestinal symptoms of Lyme disease, we may miss the early neurological or autonomic symptoms of the infection and delay effective treatment.
(C) Lyme Borreliosis Foundation
