Ecthyma gangrenosum is a dermatologic manifestation of severe infection with P. aeruginosa
has been considered to be a pathognomonic sign of P. aeruginosa bacteremia that occurs in up to 6% of patients with systemic infection
however clinically similar lesions, however, have been reported secondary to other infections e.g. E. coli, Aspergillus niger, and in patients with Candida sepsis
occurs predominantly if not exclusively in immunocompromised patients
predisposing factors include malnutrition, malignancy (especially hematological), medications (cancer chemotherapy, systemic corticosteroids, antibiotics), widespread burns, cystic fibrosis, poorly controlled diabetes mellitus, neutropaenia or pancytopaenia as a result of illness or medications
lesion of ecthyma gangrenosum typically begins as a red or purpuric macule
evolves into a hemorrhagic bulla - bulla subsequently ruptures to form a gangrenous, suppurative ulcer with a black eschar and an erythematous rim
lesions may be solitary or multiple
in bacteraemic patients commonly lesions occur in apocrine areas, but lesions also may be scattered elsewhere on the trunk and extremities
primary cutaneous infections caused by direct inoculation occur predominantly in apocrine areas - may occasionally occur at wound sites
this pattern of infection occasionally begins as folliculitis with rapid evolution into more classical ecthyma gangrenosum lesions
in echyma gangrenosum associated with bacteraemia there is a male predominance. There is a female predominance in patients with the primary cutaneous form of infection
management
requires prompt diagnosis and initiation of treatment
consider the diagnosis when a hemorrhagic bulla or gangrenous ulcer is noted on the skin of an immunocompromised patient
performa a skin biopsy for histopathologic evaluation and for bacterial culture and antibiotic susceptibility testing
obtain blood cultures
empirical intravenous antibiotic therapy should be initiated because a delay in the initiation of therapy is associated with a worse prognosis
antimicrobial regimen of choice is an antipseudomonal penicillin combined with an aminoglycoside
prognosis is often poor
Reference:
Wortman PD. Bacterial infections of the skin. Current Problems in Dermatology 1993; 5 (6):197-224.
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