Ecthyma

Ecthyma
Classification and external resources

Ecthyma
ICD-10 L08.3 (ILDS L08.830)
ICD-9 686.8
DiseasesDB 30731
MedlinePlus 000864
eMedicine derm/113
MeSH D004473

Contents

Definition and Introduction

Ecthyma is an ulcerative pyoderma of the skin caused by bacteria such as Streptococcus pyogenes, Pseudomonas and Staphylococcus aureus. Because ecthyma extends into the dermis, it is often referred to as a deeper form of impetigo.

Causes include Insect bites and an ignored minor trauma.

Ecthyma describes ulcers forming under a crusted surface infection. The site may have been that of an insect bite or of neglected minor trauma.The bacterial pathogens that cause ecthyma are usually Steptococci and Staphylococci. It is treated by antibiotics like cloxacillin, erythromycin and cefalexin.

Ecthyma has a predilection for children and elderly individuals. Outbreaks have also been reported in young military trainees

Ecthyma usually arises on the lower extremities of children, persons with diabetes, and neglected elderly patients. During wartime in tropical climates, ecthymatous ulcers are commonly found on the ankles and dorsi of the feet.

Etiology

Ecthyma can be seen in areas of previously sustained tissue injury (eg, excoriations, insect bites, dermatitis). Ecthyma can be seen in patients who are immunocompromised (eg, diabetes, neutropenia, HIV infection). Important factors contribute to the development of streptococcal pyodermas or ecthyma: ♦ High temperature and humidity ♦ Crowded living conditions ♦ Poor hygiene

Untreated impetigo that progresses to ecthyma most frequently occurs in patients with poor hygiene.

Some strains of Streptococcus pyogenes have a high affinity for both pharyngeal mucosa and skin. Pharyngeal colonization of S. pyogenes has been documented in patients with ecthyma.

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.

The difference between ecthyma and impetigo is that in impetigo the erosion is at the stratum corneum, while in ecthyma the ulcer is full thickness, and thus heals with scarring.

There is no racial or sexual dominance in Ecthyma.

Morbidity/Mortality

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%.

References

eMedicine http://emedicine.medscape.com/article/1052279-overview