A 26-year-old man who has sex with men presents to his local sexual health clinic with a 1 cm indurated painless ulcer under his foreskin

A 26-year-old man who has sex with men presents to his local sexual health clinic
with a 1 cm indurated painless ulcer under his foreskin. Dark ground microscopy is
positive for spirochaetes and he is treated for presumed primary syphilis with IM
benzathine penicillin 2.4 MU.
Six hours later he presents at the Emergency Department with a two hour history of
palpitations, fevers, headache and facial flushing.
He has never had similar symptoms in the past and his medical history is
unremarkable. He has no known drug allergies.
On examination he appears flushed and has developed a blanching maculopapular
rash on his torso. He did not notice this earlier today morning. Mucus membranes are
intact.
His heart rate is 108 beats/min with pure heart sounds. His BP is 100/70 mmHg. His
respiratory rate is 12, chest is clear and there are no abnormalities on abdominal or
neurological examinations. Fundoscopy is normal. His temperature is 37.9℃
Blood tests are taken and reveal:
Haemoglobin 140g/L (115-165 g/L)
White cell count 11.32 109
/L (4.00-11.00 109
/L)
Platelets 310 109
/L (150-400 109
/L)
Sodium 142 mmol/L (135-145 mmol/L)
Potassium 4.1 mmol/L (3.5-5.0 mmol/L)
Chloride 100 mmol/L (98-108 mmol/L)
Urea 3.5 mmol/L (2.5-7.5 mmol/L)
Creatinine 86 umol/L (40-130umol/L)
Albumin 42 g/L (32-45 g/L)
Bilirubin 14 umol/L (<20 umol/L)
Alanine transaminase 40 U/ (<50 U/L)
Aspartate transaminase 30 U/L (<40 U/L)
Alkaline phosphatase 125 U/L (40-150 U/L)
CRP 40 (<5)
ECG shows sinus tachycardia only.
How should he be managed?

Ceftriaxone 2 g IV
Change antibiotics to doxycycline
Intramuscular adrenaline
Oral prednisolone and chlorphenamine
Reassure

This is patient describes the Jarisch-Herxheimer reaction.
This is an acute febrile illness with headache, myalgia, chills and rigors starting within
12 hours of the first dose of treatment and resolving within 24 hours. It is usually not
important in early syphilis unless there is neurological or ophthalmic involvement or in
pregnancy when it may cause fetal distress and premature labour.
It occurs in ~50% of patients with primary syphilis, 90% with secondary syphilis and
25% with early latent syphilis. It is very rare in late syphilis but may be dangerous if
there are lesions around important anatomical sites (for example, sinoatrial node,
larynx).
The reaction is thought to occur due to the release of endotoxin from killed
microorganisms and is accompanied by a rise in pro-inflammatory cytokines. The
reaction was originally described with syphilis treatment but is also well described in
rickettsial diseases such as Lyme disease and Q fever.
Patients should be counselled about the reaction prior to receiving therapy for
syphilis.
There is no meningism and the evolving rash is blanching.
A single dose of benzathine penicillin should cure most cases of early syphilis, thus
no further antibiotics should be necessary.
This reaction can easily be confused with an allergic reaction, but will settle without
treatment.
Simple reassurance and consideration of the use of paracetamol for symptom control
is the appropriate management