What is ecthyma?

Ecthyma is a cutaneous infection by Streptococcus pyogenes ou Staphylococcus aureus with dermal extension. As it extends into the dermis, it is often referred to as a deeper form of impetigo.

• There are no figures for incidence but it is more frequent in children and the elderly.

• There is no apparent predilection for race or sex.

Fatores de risco

• Tissue damage from excoriations, insect bites or dermatitis and a compromised immune system as in diabetes or neutropenia, predisposes to the development of ecthyma. Other causes of immune compromise may include malignancy and teste de HIV.

• Poor hygiene aids spread as do overcrowded living conditions.

• It is more common in hot and humid climates.

• Untreated impetigo with poor hygiene may progress to ecthyma.

• Desnutrição is also a risk factor.

• Ecthyma starts like impetigo, sometimes in a pre-existing wound.

• Ecthyma usually begins as vesiculopustules with a grey-yellow crust that evolves into shallow punched-out ulcers with a necrotic base and haemorrhagic crust.¹

• Lesions can be multiple and are commonly seen on the lower extremities.

Symptoms of ecthyma

• Ecthyma usually arises on the lower legs or feet of children, those with diabetes, or neglected elderly people.

• Lesions are typically painful with associated lymphadenopathy.

• In tropical climates, ulcers are commonly found on the ankles and dorsum of the feet.

Signs of ecthyma

• The most commonly affected sites are buttocks, thighs, legs, ankles and feet.

• It starts as a vesicle or pustule over inflamed skin and then deepens to ulcerate with an overlying crust.

• The crust is grey-yellow and is thicker and harder than the crust of impetigo.

• A shallow, punched-out ulcer is seen if the crust is removed.

• The deep dermal ulcer has a raised and indurated margin.

• Ecthyma lesions may remain of constant size and resolve without treatment or they can enlarge to 3 cm in diameter.

• Ecthyma heals slowly, usually with a scar.

• Regional lymphadenopathy is common, even with solitary lesions.

• Ecthyma gangrenosum (a similar condition caused by Pseudomonas spp.).² It tends to be more severe and, if diagnosis is delayed, there is a significant mortality.

• Streptococcal ecthyma can mimic potentially serious zoonotic infections.¹

• Ecthyma contagiosum is an alternative name for orf, which can look similar.³ The diagnosis of orf is usually based on the patient's history of relevant exposure.

• Also consider:
  

  • Mordidas de insetos.

  • Leishmaniose.

  • Papulose linfomatoide.

  • Gangrena de pyoderma.

  • Sporotrichosis.

  • Venous or arterial ulcers.

• Swab for bacteriology.

• Fasting glucose or HbA1c to exclude diabetes.

• FBC for neutropenia.

Ecthyma is more likely to occur in association with diabetes or other conditions of immune compromise.

Não-medicamentoso

• Treatment depends on the progression of the disease.

• Hygiene is important. Use bactericidal soap and frequently change bed linens, towels and clothing.

• Remove crusts and apply an antibiotic ointment daily.

• Povidone-iodine and hydrogen peroxide may be used as antiseptics.

Medicamentos

• Topical mupirocin ointment is very effective. Fusidic acid is an alternative. Topical antibiotics are usually satisfactory if the infection is localised.

• More extensive lesions require oral antibiotics, possibly for several weeks to obtain full resolution.

• Penicillin should be adequate to treat streptococci.

• Se S. aureus is also present, an antibiotic resistant to penicillinase may be advised.

• Consider parenteral antibiotics if there is widespread involvement.

Cirúrgico

Gently debride the crusts if they are extensive.

• Ecthyma rarely produces systemic symptoms.

• Invasive complications of streptococcal skin infections can include cellulitis and erysipelas, gangrena, lymphangitis, suppurative lymphadenitis and bacteraemia.

• Non-suppurative complications of streptococcal skin infections include escarlatina e glomerulonefrite aguda. Antibiotics do not appear to reduce the rate of post-streptococcal glomerulonephritis.

• Possible sequelae of secondary untreated S. aureus pyodermas include cellulitis, lymphangitis, bacteraemia, osteomielite e acute infective endocarditis. Some S. aureus strains produce exotoxins that can lead to staphylococcal scalded skin syndrome e síndrome do choque tóxico.⁵

Healing is slow with scar formation but response to appropriate antibiotics occurs over several weeks.

In tropical climates, pay attention to hygiene and use insect repellents to reduce bites.