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ORAL PRESENTATION ABSTRACTS

P021 Name of Presenter: Nor Hafizah Ain Binti Mohd Zakaria, Jabatan Pergigian Pediatrik,
Hospital Kuala Lipis
Title of Presentation: Black Eschar on the Upper Lip: A Clue to the Diagnosis of
Pseudomonas Aeruginosa Infection

Abstract
Nor Hafizah Ain MZ 1,* , Chan YP 1,*
1 Jabatan Pergigian Pediatrik, Hospital Kuala Lipis

Background: Ecthyma gangrenosum (EG) is pathognomonic of underlying Pseudomonas aeruginosa
bacterial infection, characterized by the formation of a cutaneous necrotic ulceration or black eschar,
surrounded by an erythematous halo. EG lesions are a result of perivascular bacterial invasion in the
cutaneous tissues, leading to necrotizing vasculitis. It is uncommon in healthy individuals, with only six
percent of lesions affecting the facial region.
Case Report: A febrile 10-month-old Malay girl presented with facial swelling originating from an insect
bite on her left upper lip. Within a day, the solitary red swelling at the bite site had evolved into an eschar-
covered ulcer, before progressing rapidly to facial cellulitis. Examination revealed a black eschar encrusted
over a necrotic skin ulcer on the vermillion border of her left upper lip, surrounded by erythema and swelling
extending to the left maxilla. Her past medical history was non-contributory. The patient’s febrile condition,
full blood count and elevated C-Reactive Protein results suggested an infectious etiology rather than an
allergic reaction to the insect bite. A cutaneous swab for culture and sensitivity revealed Pseudomonas
aeruginosa, confirming the diagnosis of Ecthyma gangrenosum. A combination of anti-pseudomonal
beta-lactam (Tazocin) and an aminoglycoside (Amikacin) was implemented. Despite intravenous antibiotic
therapy, she showed slow improvement in healing. Debridement of the necrotic ulcer was performed with
chlorhexidine daily, and healing by secondary intention was closely monitored. Minimal scabbing was
observed on the vermillion border two months later during follow-up.
Conclusion: Pseudomonas aeruginosa infections are difficult to eradicate due to the organism’s capability of
delaying wound healing and developing drug-resistance. Cutaneous manifestations of EG may result from
primary inoculation or hematogenous dissemination in bacteremic patients. This case report highlights
the importance of recognizing the distinct features of pseudomonas infection. An early diagnosis facilitates
the initiation of appropriate antibiotics and effective wound management, crucial for enhancing patient
outcomes.

Key words: Ecthyma Gangrenosum, Pseudomonas Aeruginosa Infection, Anti-Pseudomonal antibiotic,
Skin lesion, Facial

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