A rare case of acute generalised exanthematous pustulosis like Sweet's Syndrome.

Abstract

Sweet's Syndrome, also known as acute febrile neutrophilic dermatosis, is a neutrophilic dermatosis characterised by fever and acute onset of tender, erythematous plaques or nodules. Whilst the pustular variant of Sweet's Syndrome is well recognised, the acute generalised exanthematous pustulosis (AGEP) like presentation is rare. We report a case of AGEP like Sweet's Syndrome in a 72- year-old man who presented with a pustular eruption affecting the face, neck and trunk associated with fever (up to 40.3degreeC) following ceftriaxone, azithromycin and metronidazole for presumed aspiration pneumonia in the setting of ischaemic stroke. He was initially diagnosed as AGEP given the clinical presentation. However, he continued to deteriorate clinically despite cessation of offending medications, necessitating treatment with prednisolone. Histology subsequently revealed papillary oedema and dense mononuclear neutrophilic infiltrate in the dermis, staining positive for myeloperoxidase. There were no intraepidermal neutrophils or subcorneal pustules. A diagnosis of AGEP-like histiocytoid Sweet's Syndrome was made. The patient responded to weaning dose of prednisolone with no recurrence of cutaneous eruption. His malignancy screen was significant for a positive faecal occult blood test and elevated CA 19-9, and an outpatient gastroscopy and colonoscopy were organised. This case highlights the importance of recognising AGEPlike Sweet's Syndrome as a differential for patients who present clinically as AGEP, especially in those who continue to deteriorate despite cessation of offending medications. It is important to differentiate this rare form of Sweet's Syndrome from AGEP because of different potential causative factors and organ system involvement along with differing disease progression and intervention. Biopsy of all cases of suspected AGEP is recommended.