A 28 year old female presented on a weekend after feeling unwell for about 5 days, she thought she had a cold/flu but it wasn’t improving so she came to the ED. She complained of very non-specific symptoms: mild headache, lethargy, felt a bit feverish, mild joint stiffness/pain. There were no coryzal symptoms – runny nose, cough, sore throat or sneezing.

She had not felt like eating and drinking but was able to ‘force’ herself and was able to keep food/fluids down. She had been passing urine normally with no symptoms. There was no nausea or vomiting. There was no neck pain or headache or photophobia.

Past Medical History : Normally fit and well

Drug History: Nil regularly, NKDA.

Social History: Independent, lived alone, she worked in IT and she was in the Army Reserve. No recent foreign travel.

She looked ok. Had normal vital signs, not tachycardic, normal BP, temperature of 37.8.

ENT – normal, no lymphadenopathy.
Respiratory  – chest clear, normal RR, Spo2 98%.
Abdominal  – Soft, non-tender, no organomagely, bowel sounds normal.
CNS – normal. Normal Gait. Normal neck movements, no photophobia. Kernig’s negative.

She reported no rashes but did mention that she had a red patch on her LEFT upper calf.
Skin – approx. 6cm x 6cm red ‘bullseye’ patch popliteal fossa

Further questioning she had been on exercise with the Army 10days previously

Differential Diagnosis 

Diganosis Rationale
Lyme disease Had a typical erythema migrans type rash

Had been in a forested area within the last 2 weeks

The area had been in a high-risk area.


Cellulitis Another common reason for localised redness and systemic illness

Can be very difficult to distinguish erythema migrans rash


Local inflammation secondary to insect bite Unlikely in this case

Can give localised reaction to bite

Usually transient and self-limiting

Can have some short term systemic symptoms but would be unusual for them to remain for this long


Urinalysis – NAD
Pregnancy test – NAD
VBG: Lactate 0.9, gluc 7.1
LFT, U&E, FBC, CRP (done at triage) – all normal

Lyme disease

Doxycycline 100mg BD for 21 days.


Nice have guidelines that are currently going through validation and consultation process – out April

Essentially their recommendation is:

Diagnose Lyme disease in people with EM lesion; that is
red, that increases in size and sometimes has central clearing
not itchy or painful
1-4 weeks post tick bite or potential exposure

Diagnose and treat those who have EM lesion with laboratory testing
Only offer testing if there is a clinical suspicion of Lyme disease using two tier method

Doxycline 100mg BD for 21 days is found to be 95% cure in early Lyme

Lyme Disease
Approximately 2000-3000 cases a year
Most common tick-borne illness in the northern hemisphere
Caused by borrelia burgdorferi
Risk is variable throughout the UK. Ticks are common in areas such as woodland and heath areas and whilst cases can happen throughout the UK, high risk areas include, Exmoor, the lake district, the new forest, the highlands.
Ticks are less active in winter and dry summer so cases tend to be around late spring, early summer, and autumn.
A good number of patients do not remember a tick or bite. – suggested 64% of patients in Europe do not recall tick bite.
It seems that the tick needs to be attached for 24-48h for the greatest risk of transmission, attachment for less than 24h means transmission is remote and greater than 72h almost certain.

Exposure to symptom development is often delayed, typically 7-14 days post exposure but ranges 2-30 days.
Symptoms vary depending on the stage of illness
Early localised disease
Early disseminated disease
Late Lyme disease

Probably most common clinical encounter is with patients between early localised and early disseminated disease stages

Early symptoms include the characteristic erythema migrans skin lesion (80-90% of cases) although can sometimes be difficult to distinguish and is asymptomatic or unnoticed as it is in hard to see places (pop fossa, axilla etc). Sometimes multiple multiple skin lesions multiple annular erythematous lesions similar to, but usually smaller than, the primary lesion.
Often it is also associated with non-specific vial syndrome symptoms such as:
Fatgue 50%
Headache 40%
Myalgia 40%
Arthralgia 40%
Regional lymphadenopathyathy 20%
Fever 20%.

Early disseminated acute neurologic or cardiac involvement usually occurs weeks to several months after the tick bite and may be the first manifestation of Lyme disease.
unilateral or bilateral cranial nerve palsies
Cardiac manifestations of Lyme disease include fluctuating degrees of atrioventricular heart block, sometimes with myopericarditis, which is usually mild when it occurs

Late disseminated — Late Lyme disease occurs months to a few years after the onset of infection and may not be preceded by a history of early localized or disseminated Lyme disease
arthritis in one or a few joints is the most common feature of patients with late Lyme disease
neurologic symptoms – reported in about 15-25% (neuroborrelios), such as a subtle encephalopathy, facial (bil/uni) palsy, meningitis
Cardiac Symtpoms – palpitations are common but pericarditis and conductions are rare
patients may develop a chronic skin condition called acrodermatitis chronica atrophicans

UK follows 2-tier approach to testing
testing for common Ab to B. Burgdorferi (ELISA)
progress to specific immunoblot if suspicious or positive
However there are difficulties with lab testing for Lyme disease (largely due to the unknown timescales of disease)
False negatives are common in early disease because antibodies take several weeks to get to datectable level
False positives are also positive due to cross-reactive antibodies from syphonllis, epstein bar etc
Specific IgM antibodies appear first, usually 3–4 weeks after the infection begins. These antibodies peak after 6–8 weeks and subsequently decline

Specific IgG antibodies usually appear 6–8 weeks after the onset of the infection. These antibodies peak in 4–6 months

Useful Links

NICE guidance on Lyme Disease

Erythema Migrans