Definition and Introduction

Ecthyma is an ulcerative pyoderma

Pyoderma

Pyoderma means any skin disease that is pyogenic. These include superficial bacterial infections such as impetigo, impetigo contagiosa, ecthyma, folliculitis, Bockhart impetigo, furuncle, carbuncle, tropical ulcer, etc. Autoimmune conditions include pyoderma gangrenosum...

 of the skin caused by bacteria such as Streptococcus pyogenes

Streptococcus pyogenes

Streptococcus pyogenes is a spherical, Gram-positive bacterium that is the cause of group A streptococcal infections. S. pyogenes displays streptococcal group A antigen on its cell wall. S...

, Pseudomonas and Staphylococcus aureus

Staphylococcus aureus

Staphylococcus aureus is a facultative anaerobic Gram-positive coccal bacterium. It is frequently found as part of the normal skin flora on the skin and nasal passages. It is estimated that 20% of the human population are long-term carriers of S. aureus. S. aureus is the most common species of...

. Because ecthyma extends into the dermis, it is often referred to as a deeper form of impetigo

Impetigo

Impetigo is a highly contagious bacterial skin infection most common among pre-school children. People who play close contact sports such as rugby, American football and wrestling are also susceptible, regardless of age. Impetigo is not as common in adults. The name derives from the Latin impetere...

.

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 Flucloxacin, 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

HIV

Human immunodeficiency virus is a lentivirus that causes acquired immunodeficiency syndrome , a condition in humans in which progressive failure of the immune system allows life-threatening opportunistic infections and cancers to thrive...

 infection).
Important factors contribute to the development of streptococcal pyodermas or ecthyma:
♦ High temperature and humidity
♦ Crowded living conditions
♦ Poor hygiene

Untreated impetigo

Impetigo

Impetigo is a highly contagious bacterial skin infection most common among pre-school children. People who play close contact sports such as rugby, American football and wrestling are also susceptible, regardless of age. Impetigo is not as common in adults. The name derives from the Latin impetere...

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%.