Background
Ecthyma is an ulcerative pyoderma of the skin caused by group A beta-hemolytic streptococci. Because ecthyma extends into the dermis, it is often referred to as a deeper form of impetigo.
Typical ecthyma lesions of the lower extremities.
The stages of ecthyma. The lesion begins as a pustule that later erodes and ultimately forms an ulcer. Pathophysiology
Ecthyma begins similarly to superficial impetigo. Group A beta-hemolytic streptococci may initiate the lesion or may secondarily infect preexisting wounds. Preexisting tissue damage (eg, excoriations, insect bites, dermatitis) and immunocompromised states (eg, diabetes, neutropenia) predispose patients to the development of ecthyma. Spread of skin streptococci is augmented by crowding and poor hygiene.
Epidemiology
Frequency
International
The exact incidence of ecthyma worldwide remains unknown.
Mortality/Morbidity
Ecthyma rarely leads to systemic symptoms or bacteremia. Lesions are painful and can have associated lymphadenopathy. Secondary lymphangitis and cellulitis can occur. Ecthyma does heal with scarring. The rate of poststreptococcal glomerulonephritis is approximately 1%.
Race
No racial predisposition is recognized for ecthyma.
Sex
No sexual predisposition is recognized for ecthyma.
Age
Ecthyma has a predilection for children and elderly individuals. Outbreaks have also been reported in young military trainees.[1]
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