Lyme Disease and Fatty Liver: Symptoms and NHS Care

Lyme disease and fatty liver disease are two distinct conditions that can overlap in ways that complicate diagnosis and management. Lyme disease, caused by the bacterium Borrelia burgdorferi, is known to cause liver inflammation and elevated liver enzymes in some people, which may temporarily worsen pre-existing fatty liver disease. Understanding how these conditions interact, what symptoms to look out for, and how both are managed through the NHS is important for anyone navigating a diagnosis of either condition. This article outlines the key clinical facts, diagnostic approaches and treatment options available in the UK.

Can Lyme disease cause or worsen fatty liver disease?

Lyme disease can cause temporary liver inflammation that may worsen pre-existing fatty liver disease, but it has not been shown to directly cause fatty liver disease, which is driven by metabolic risk factors.

Lyme disease can cause liver inflammation, and there is some evidence that this may temporarily worsen pre-existing fatty liver disease, though a direct causal link between Lyme disease and the development of fatty liver disease has not been established. Lyme disease is a tick-borne bacterial infection caused by Borrelia burgdorferi, transmitted through the bite of infected ticks.^[1] It is primarily known for its effects on the skin, joints, nervous system and heart, but hepatic involvement is a recognised, if less commonly discussed, feature.

Elevated liver enzymes, particularly alanine aminotransferase (ALT) and aspartate aminotransferase (AST), have been documented in a proportion of people with confirmed Lyme disease.^[16][17] This suggests that the liver can be affected during active infection, likely through a combination of direct bacterial effects and the body's inflammatory immune response. Lyme-related hepatitis is generally mild and tends to resolve once the underlying infection is treated.^[16][18] In people who already have fatty liver disease, this additional inflammatory burden may temporarily worsen liver function.

It is important to note that fatty liver disease itself is strongly associated with metabolic risk factors such as obesity, type 2 diabetes, high cholesterol and excess alcohol consumption. Lyme disease does not cause these underlying metabolic conditions. However, the systemic inflammation triggered by Borrelia infection, combined with the fatigue and reduced physical activity that often accompany illness, could theoretically create conditions less favourable to liver health in vulnerable individuals.

A note on terminology: UK clinical guidance from NICE uses the term non-alcoholic fatty liver disease (NAFLD). Professional bodies increasingly use metabolic dysfunction-associated steatotic liver disease (MASLD) to reflect the metabolic origins of the condition. Both terms refer to the same spectrum of disease, and this article uses NAFLD in line with current NICE guidance (NG49).

If you have been diagnosed with Lyme disease and have a known history of liver problems, it is sensible to discuss this with your GP, who can arrange appropriate monitoring and coordinate your care.

What are the symptoms when Lyme disease and liver problems overlap?

Overlapping symptoms include fatigue, nausea, right upper abdominal discomfort and loss of appetite; jaundice is uncommon but has been reported in more significant Lyme-related hepatitis.

When Lyme disease and liver problems occur together, the overlapping symptoms can include fatigue, nausea, right-sided upper abdominal discomfort, loss of appetite and, in some cases, mild jaundice, though many people with liver enzyme abnormalities during Lyme disease experience no specific liver symptoms at all. This makes clinical awareness and appropriate testing particularly important.

Lyme disease itself produces a wide range of symptoms depending on the stage of infection. Early localised disease typically presents with the characteristic expanding rash known as erythema migrans, alongside flu-like symptoms including fever, muscle aches and headache. In UK practice, erythema migrans is considered diagnostic of Lyme disease and warrants antibiotic treatment without waiting for serology results, in line with NICE guideline NG95.^[2] As the infection progresses, symptoms can affect multiple body systems. Fatigue, which is one of the most commonly reported symptoms of Lyme disease, is also a hallmark of liver dysfunction, making it difficult to attribute this symptom to one cause alone.

Nausea and reduced appetite are shared features of both conditions. Mild jaundice, characterised by a yellowing of the skin or whites of the eyes, is uncommon but has been reported in cases where Lyme disease causes more significant hepatitis. Upper right abdominal discomfort or a sense of fullness may reflect liver enlargement (hepatomegaly), which can occur in both Lyme-related hepatitis and fatty liver disease.

Because these symptoms overlap considerably, it is not possible to distinguish Lyme-related liver involvement from other causes of liver disease on the basis of symptoms alone. The following symptoms warrant prompt medical attention:

• New or worsening jaundice (yellowing of the skin or eyes): contact your GP on the same day or call NHS 111

• Pale stools or very dark urine alongside jaundice: seek same-day assessment

• Severe right upper abdominal pain with fever: seek urgent assessment, as this may indicate a more serious condition

• Confusion, disorientation or difficulty staying awake: call 999 or go to your nearest emergency department

• Signs of gastrointestinal bleeding (vomiting blood or passing black, tarry stools): call 999

Anyone experiencing persistent fatigue, jaundice or abdominal discomfort alongside a known or suspected Lyme disease diagnosis should contact their GP for assessment.

How is fatty liver diagnosed and monitored in people with Lyme disease?

Diagnosis uses liver function tests, FIB-4 index scoring and abdominal ultrasound; in Lyme disease, elevated enzymes may reflect active infection, so repeat testing after antibiotic treatment is recommended.

Fatty liver disease is diagnosed primarily through blood tests and imaging, and in people with Lyme disease, the same investigative pathway applies, with the added consideration that Lyme-related liver inflammation may temporarily alter test results. A GP will typically begin with liver function tests (LFTs), which measure enzymes including ALT, AST, alkaline phosphatase (ALP) and bilirubin, alongside a full blood count, urea and electrolytes (U&Es), glucose or HbA1c, and a lipid profile.

Where LFTs are abnormal, it is standard practice to consider and exclude other common causes, including viral hepatitis (hepatitis B and C serology), autoimmune liver disease, alcohol use and any medications that may affect the liver. This helps to ensure that a diagnosis of NAFLD is not made without appropriate exclusion of other conditions.

In the context of Lyme disease, elevated liver enzymes may reflect active infection rather than established fatty liver disease. NICE guideline NG49 on NAFLD recommends using the FIB-4 index as a first-line non-invasive tool to assess the risk of liver fibrosis in adults.^[5][8] FIB-4 uses age, ALT, AST and platelet count to generate a score; age-specific thresholds are used to guide further investigation.^[8][9] Where FIB-4 results are indeterminate or elevated, the Enhanced Liver Fibrosis (ELF) test may be used in adults to further risk-stratify before referral decisions are made.^[5][6] Clinicians should verify the current NICE NG49 threshold values before applying them, as these may be updated.

Ultrasound of the abdomen is the most commonly used imaging modality for detecting fatty changes in the liver and is widely available through NHS services. It is non-invasive, does not involve radiation and can identify hepatomegaly or increased echogenicity consistent with fat deposition. Transient elastography (FibroScan) may be arranged to assess liver stiffness as a marker of fibrosis, complementing rather than replacing the NICE NG49 pathway.

For people being treated for Lyme disease, it is reasonable to repeat liver function tests after completing antibiotic therapy to determine whether enzyme abnormalities resolve, which would suggest they were infection-related rather than indicative of underlying chronic liver disease. Your GP can coordinate this monitoring and refer to a hepatologist or gastroenterologist if results remain abnormal.

What treatment options are available through the NHS?

NHS treatment focuses on antibiotics for Lyme disease (doxycycline first-line per NICE NG95) and lifestyle modification for fatty liver disease; no medicines are currently licensed in the UK specifically for NAFLD.

NHS treatment for Lyme disease centres on antibiotic therapy, and there is no specific licensed treatment for Lyme-related liver inflammation, which typically resolves once the underlying infection is treated.

NICE guideline NG95 on Lyme disease sets out antibiotic regimens according to the presentation and stage of disease. Doxycycline is the recommended first-line oral antibiotic for erythema migrans and several other manifestations.^[2] Amoxicillin is an alternative where doxycycline is not suitable. Azithromycin is reserved for specific situations where both doxycycline and amoxicillin are not appropriate, and is not a blanket alternative for all presentations. For certain manifestations, including some forms of Lyme neuroborreliosis and Lyme carditis, intravenous ceftriaxone may be indicated.^[3][4] Treatment durations vary by presentation and are specified in NG95; for disseminated disease they are typically in the range of 21 to 28 days, but clinicians should follow the presentation-specific recommendations in the guideline.

Doxycycline is generally avoided in pregnancy, during breastfeeding and in children under 12 years of age.^[10][11] In these groups, NG95 provides specific alternative regimens, typically using amoxicillin. Anyone in these groups who requires treatment for Lyme disease should discuss the most appropriate antibiotic choice with their GP or specialist.

People with both conditions should ensure their GP is aware of all medications they are taking, as some antibiotics used in Lyme disease treatment, including doxycycline, can occasionally affect liver enzymes. This does not usually require stopping treatment but may warrant closer monitoring in those with pre-existing liver disease. Persistent or significantly abnormal LFTs warrant GP review and possible referral to hepatology.

For fatty liver disease managed through the NHS, treatment is primarily focused on addressing the underlying metabolic risk factors. NICE guidance (NG49) recommends weight management, dietary modification and increased physical activity as the cornerstone of management. Where type 2 diabetes or dyslipidaemia are present, optimising control of these conditions is a priority. At the time of writing, no medicines are specifically licensed in the UK for the treatment of NAFLD, though research in this area is ongoing; clinicians should check the current BNF and MHRA authorisations for the latest position.^[13][14]

If you experience any suspected side effects from medicines prescribed for Lyme disease or liver conditions, you can report these to the MHRA via the Yellow Card scheme at yellowcard.mhra.gov.uk.

Referral pathways through the NHS may involve a hepatologist for complex liver disease, an infectious disease specialist for Lyme disease, or both. Integrated care boards (ICBs) commission these specialist services locally, and access may vary by region. Your GP is the appropriate first point of contact to initiate referrals and coordinate care between specialties.

Lifestyle changes that can support liver health during Lyme disease recovery

A Mediterranean-style diet, reduced alcohol intake and gradual physical activity are recommended by NICE NG49 and the British Liver Trust to reduce liver fat and support recovery.

Adopting supportive lifestyle measures can meaningfully benefit liver health during and after Lyme disease recovery, particularly for those with co-existing fatty liver disease. The liver plays a central role in metabolism, immune function and detoxification, and supporting it through evidence-based lifestyle choices is a practical and accessible step.

Diet is one of the most important modifiable factors. A Mediterranean-style diet, rich in vegetables, legumes, wholegrains, oily fish and olive oil, has a strong evidence base for reducing liver fat and inflammation, and is consistent with the dietary approach recommended by NICE (NG49) for people with NAFLD.^[5][22] NICE NG49 advises limiting free sugars and saturated fat and following a balanced, varied diet; the British Liver Trust similarly recommends reducing intake of foods high in refined sugars and saturated fats. Alcohol should be avoided or minimised, as even moderate consumption can worsen liver inflammation, particularly during active infection or recovery.

Physical activity supports liver health by reducing hepatic fat and improving insulin sensitivity. The UK Chief Medical Officers' guidelines recommend at least 150 minutes of moderate-intensity activity per week for adults.^[19][20] During Lyme disease recovery, fatigue may limit exercise capacity, so a gradual, paced approach is advisable. Activities such as walking, swimming or gentle cycling can be introduced incrementally as energy levels allow.

Weight management is particularly relevant for those with NAFLD. NICE NG49 and supporting evidence from professional bodies including the British Society of Gastroenterology indicate that a reduction in body weight of around 5 to 10 per cent is associated with meaningful reductions in liver fat and improvements in liver enzyme levels in people with NAFLD.^[5][22]

Other supportive measures include:

• Staying well hydrated

• Maintaining regular sleep patterns, which support immune recovery

• Avoiding unnecessary over-the-counter medications that are metabolised by the liver unless clinically indicated; if you have liver disease, check with your GP or pharmacist before taking any over-the-counter medicines, including paracetamol at higher doses

If you are unsure which lifestyle changes are appropriate for your individual circumstances, your GP or a registered dietitian can provide personalised guidance.

Scientific References

1. Lyme disease: diagnosis and management (NG95).
2. NG95 Recommendations chapter.
3. NG95 Evidence review 7: management of Lyme disease (neuroborreliosis/ceftriaxone).
4. NG95 Evidence review I: management of Lyme carditis.
5. Non-alcoholic fatty liver disease (NAFLD): assessment and management (NG49).
6. NG49 Recommendations for research (MASLD/NAFLD).
7. Non-Alcoholic Fatty Liver Disease: Assessment and Management (NGC UK).
8. Alcoholic fatty liver disease [DAP59] – Protocol (FIB-4 thresholds).
9. Using the ELF test, FIB-4 and NAFLD fibrosis score to assess liver fibrosis.
10. Doxycycline – BNF.
11. Doxycycline: antibiotic for bacterial infections.
12. Tetracycline – BNF (tetracycline class contraindications in pregnancy).
13. Resmetirom (Rezdiffra) authorised to treat metabolic dysfunction-associated steatohepatitis (MASH) in adults.
14. Non-alcoholic fatty liver disease (NAFLD).
15. GID-TA11477 Draft scope post-referral (no medicines approved for MASLD/MASH in UK).
16. Horowitz HW et al. Liver function in early Lyme disease.
17. Early disseminated borreliosis with multiple erythema migrans and elevated liver enzymes: case report and literature review. Acta Derm Venereol.
18. Kowalski TJ et al. Antibiotic treatment duration and long-term outcomes of Lyme disease.
19. Physical activity guidelines: UK Chief Medical Officers' report.
20. UK Chief Medical Officers' physical activity guidelines (full text).
21. Physical activity guidelines for adults aged 19 to 64.
22. Impact of weight loss and reduction of ultra-processed foods on liver fat content in MASLD: a randomised controlled trial. JHEP Reports.
23. Very low energy ketogenic diet vs Mediterranean diet for MASLD: superior steatosis reduction in a randomised pilot study. JHEP Reports.
24. Comparative efficacy of different diet modalities on metabolic profiles and liver functions in MAFLD: a network meta-analysis. BMC Gastroenterology.

Frequently Asked Questions