An unusual cause of a necrotic bullous skin lesion: a case report

Tularaemia is a zoonotic infection uncommon in Switzerland, but its incidence is increasing. Thus, tularaemia should also be considered in returning travellers with compatible exposure history. We report a case of ulceroglandular tularaemia presenting with a necrotic bullous skin lesion.

A man in his 30s presented with a necrotic bullous lesion on the right palm, accompanied by ipsilateral axillary and supraclavicular lymphadenopathy. Eleven days prior, during a stay in Canada, he developed an itchy skin lesion and reported direct contact with a hare carcass five days before symptom onset. He initially received antibiotic therapy with a cephalosporin, which did not result in clinical improvement. A swab obtained from the lesion tested positive for Francisella tularensis subsp. tularensis by polymerase chain reaction (PCR), and serology confirmed the result.

Antibiotic therapy was initially switched to doxycycline (100 mg twice daily), but discontinued after 6 days because of a sore throat suggestive of oesophageal irritation. Ciprofloxacin (500 mg twice daily) was subsequently administered for 10 days, during which the lesion, lymphadenopathy and general symptoms resolved rapidly. This case highlights the importance of thorough exposure history and the early consideration of tularaemia in patients with necrotic skin lesions and regional lymphadenopathy, particularly when there is no response to standard antibiotic therapy. Early diagnosis allows for appropriate antimicrobial treatment and favourable outcomes.