Tick-borne illness in the UK: diagnostic pathways, testing and functional treatment

Where I stand, before anything else

Few areas of medicine are as polarised as this one. People arrive having been told by one clinician that chronic Lyme disease is a fiction and by another that it explains everything, and neither position has helped them get better.

My position is this. Lyme disease is real, under-diagnosed in its early stages in the UK, and treatable. A proportion of people remain unwell after correctly treated Lyme disease, and their symptoms are real; the mechanism is uncertain and probably differs between people. Unvalidated tests over-diagnose infection in people whose symptoms have another cause, and prolonged antibiotic treatment based on those tests has been tested in randomised trials and does not work. I hold all of those at once, and I will not pretend the picture is simpler than it is.

I am a hospital doctor and a certified functional medicine practitioner. I assess tick-borne illness in Twickenham and Richmond and online, and this guide sets out how.

Why UK Lyme testing is inadequate, and in which direction

The UK follows a two-tier serological pathway, set out in NICE guideline NG75. A screening ELISA looks for antibodies to Borrelia; if it is positive or equivocal, a confirmatory immunoblot is run, in England by the UK Health Security Agency's Rare and Imported Pathogens Laboratory at Porton Down. The tests are good at what they are designed for, and their limitations are well known and specific.

It misses early infection

Antibodies take weeks to appear. In the first few weeks after a bite, the ELISA is negative in a substantial proportion of people who are genuinely infected. NICE is explicit about this: erythema migrans, the expanding red rash, is a clinical diagnosis and should be treated without waiting for a test; and a negative test in the first four weeks does not exclude Lyme disease if the clinical suspicion is high. The guideline says to repeat the ELISA four to six weeks after the first test, and to consider an immunoblot if symptoms have persisted twelve weeks or more with a negative ELISA. In practice that pathway is often not followed. A single negative test, taken too early, closes the case, and the person is told they do not have Lyme disease when the honest answer was 'not yet detectable'.

It cannot tell active from past infection

Antibodies persist for years after successful treatment. A positive test in someone who has had Lyme disease before, or who was exposed and cleared it, says nothing about whether infection is present now. There is no widely available, validated test for active infection in later disease.

And some private tests over-diagnose

This is the other direction, and it matters as much. A number of laboratories abroad, and some in the UK, offer tests that NICE specifically advises against because they have not been validated: lymphocyte transformation tests (sold under names such as EliSpot), CD57 lymphocyte counts, and in-house immunoblots with non-standard interpretation criteria. These tests return positive results in a large fraction of people tested, including healthy controls. People with fatigue, pain and brain fog from another cause are told they have Lyme disease and several co-infections, and are then treated for infections they do not have, sometimes for years.

I see the results of these tests regularly, and I understand why people have them done: they were told the NHS test was negative and the symptoms did not go away. But a test that is positive in most people who take it is not measuring what it claims to.

What UK ticks actually carry: the co-infection framework

The co-infection panels sold by some laboratories list a dozen organisms, and results commonly come back positive for several of them. It is worth setting that against what is actually known about UK ticks.

The point is not that co-infection never happens. It is that a panel returning Borrelia plus Babesia plus Bartonella plus Mycoplasma in a person bitten in Surrey is describing the laboratory's methods, not the epidemiology of Surrey. A framework has to start from what is plausible.

How I assess persistent symptoms

Most of the people who come to me are not in the acute phase. They were bitten, or think they were, months or years ago; they may or may not have been treated; and they are exhausted, in pain, foggy, and have been passed around. For that group the assessment has three parts, and the order matters.

1. Reconstruct the history. Where and when the exposure was, whether there was a rash, what the original illness looked like, what treatment was given and for how long, and how symptoms have evolved. This is where most of the diagnostic information is, and it takes time, which is why the initial consultation is two hours.
2. Test for Lyme disease properly. Two-tier serology from an accredited laboratory, interpreted against the history. Where the picture suggests neurological Lyme disease, that needs NHS infectious disease or neurology input, and I will make the referral.
3. Look properly for everything else. This is the part that is most often skipped, on both sides of the argument. Thyroid disease, iron deficiency, B12 deficiency, sleep apnoea, autoimmune disease, insulin resistance, perimenopause, reactivated Epstein-Barr, chronic inflammatory response syndrome from a water-damaged building, and ME/CFS all produce this picture. Several are far more common than Lyme disease, and all of them are more treatable when found. I have set out that wider workup in the chronic fatigue guide.

What emerges from that process is one of three things: evidence of Lyme disease that was never adequately treated, in which case treatment follows NICE; a clear alternative diagnosis, which is treated on its own merits; or the genuinely difficult group in whom Lyme disease was treated correctly and symptoms persist, with no other explanation found. That last group is real, and NICE acknowledges it, recommending assessment of ongoing symptoms and supportive management rather than further antibiotics.

The treatment approach

Acute and confirmed Lyme disease

Treatment follows NICE NG75, and it works. For erythema migrans or non-focal symptoms in adults, doxycycline for twenty-one days, with amoxicillin or azithromycin as alternatives. Lyme arthritis, doxycycline for twenty-eight days. Neurological Lyme disease affecting the peripheral nerves, doxycycline for twenty-one days. Where treatment was inadequate first time, a second course is reasonable. Most people recover fully.

Persistent symptoms after treatment

Here the evidence is clear in one respect and honest about uncertainty in the rest. Four randomised controlled trials in the United States and Europe, including the PLEASE trial published in the New England Journal of Medicine in 2016, compared prolonged antibiotic treatment against placebo in people with persistent symptoms attributed to Lyme disease. None showed a benefit, and the treatments carried real harms. Both the IDSA guideline of 2020 and NICE reach the same conclusion. ILADS, the body most associated with the chronic Lyme position, recommends longer and individualised antibiotic courses; I have read its guidance and I do not find that it answers the trial evidence.

So I do not prescribe prolonged, escalating or rotating antibiotic regimens for persistent symptoms. What I do instead is the unglamorous work that the trials point towards and that most people in this position have never had:

• Sleep, assessed and treated, because nothing improves while it is disordered
• Correction of what the wider testing found: iron, B12, vitamin D, thyroid, insulin resistance, hormonal contributors
• Pacing where post-exertional malaise is present, on the same principles as ME/CFS
• Pain management that does not rely on escalating medication, including the role of sleep, inflammation and central sensitisation
• Gut and immune support where the stool analysis or inflammatory markers are abnormal, with an honest account of which interventions have evidence and which are a reasonable trial
• Environmental assessment where the history points to a water-damaged building, because chronic inflammatory response syndrome overlaps heavily with this picture and is frequently the actual problem
• Immune modulation strategies including micro-immunotherapy, which I offer within the functional medicine service and which I will describe to you as what it is: a low-dose approach with a limited evidence base, used as an adjunct and never in place of the above

This is slow work. Long-standing illness of this kind improves gradually if it improves at all, and I would rather say that now than have you disappointed at three months.

When to consider intravenous therapy

People ask about this often, and it is worth separating two very different things.

Intravenous antibiotics

There are established indications, all set out in NICE NG75, and all of them are NHS specialist territory: Lyme disease affecting the central nervous system, Lyme carditis with heart block or haemodynamic compromise, and Lyme arthritis that has not responded to oral treatment. In those situations intravenous ceftriaxone is the right treatment, it is given under infectious disease or neurology supervision, and if your assessment suggests you are in one of those groups I will refer you.

Intravenous antibiotics for persistent symptoms after treated Lyme disease are not indicated. That is the specific question the trials answered. Prolonged intravenous ceftriaxone in that setting has caused serious harm, including line infections, gallbladder disease and deaths, without benefit. I do not offer it and I will not refer you to anyone who does.

Intravenous nutrient therapy

High-dose intravenous vitamin C, glutathione, and vitamin cocktails are widely marketed to people with tick-borne illness and chronic fatigue. The evidence that they improve outcomes in either condition is weak to absent, they are expensive, and they are not without risk. I do not offer them as a treatment for Lyme disease or persistent symptoms. Where a specific deficiency cannot be corrected orally, which is uncommon, that is a different matter and I will say so.

What it costs

Lyme disease and tick-borne illness are assessed under a dedicated service; the initial consultation is two hours, and the fee, follow-up fees and what is included are on the fees page. Biotoxin illness and chronic inflammatory response syndrome, which overlap with this picture, are listed separately there. Testing is additional and I give a written estimate before anything is ordered.

A discovery call is free, and it is the right place to find out whether my approach is the one you want. If you are looking for a practitioner who will confirm chronic Lyme disease on the basis of a private panel and treat aggressively on that basis, I am not that doctor, and it is fairer to say so here than after you have paid for a consultation.