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Overview

What Is Ecthyma?

Ecthyma is a bacterial skin infection that forms sores beneath thick crusts. It is commonly caused by Staphylococcus aureus or Streptococcus bacteria. Unlike ordinary impetigo, ecthyma affects deeper layers of skin and can form ulcers. It can affect children and adults, especially when the skin is damaged or a person has health conditions that weaken infection defenses.

Symptoms

Ecthyma Symptoms

Ecthyma often starts as a small blister or pustule. It can then develop into a painful, deeper ulcer covered by a thick gray-yellow or brown crust.

  • Painful sores may develop on the skin.
  • Thick gray-yellow or brown crusts may cover the lesions.
  • An ulcer, or open sore beneath the crust, may be visible.
  • Redness may surround each lesion.
  • The skin around a sore may become swollen.
  • Lesions may itch, which can increase scratching and spread.
  • Fluid or pus may drain from a sore.
  • Dark or lighter marks may remain after healing.

Lesions most often occur on the legs, but ecthyma can also affect the buttocks, arms, or face. Multiple sores may occur at the same time, including in different areas.

How It Spreads

How Ecthyma Spreads

Ordinary ecthyma usually develops when Staphylococcus or Streptococcus bacteria enter broken, irritated, or scratched skin. The infection can spread through direct skin contact, shared towels or clothing, or from one lesion to another when a person scratches or rubs it. These are common ecthyma causes and also explain why impetigo and ecthyma can spread among close contacts.

  • Touching an infected sore can transfer bacteria to another person or to broken skin.
  • Sharing towels, clothing, bedding, or other personal items can spread bacteria.
  • Scratching or rubbing lesions can move bacteria to nearby skin or other body areas.
  • Contact with bacteria-contaminated surfaces can contribute to spread when skin is damaged.

Risk Factors

Ecthyma Risk Factors

  • Young children and older adults may be more vulnerable to ecthyma.
  • A weakened immune system can make it harder to control a bacterial skin infection.
  • Diabetes and other chronic illnesses may increase the risk of infection or slow healing.
  • Poor circulation or other conditions that reduce skin defenses can contribute to risk.
  • Eczema or scabies can damage the skin barrier and make infection more likely.
  • Insect bites can create openings through which bacteria enter.
  • Untreated cuts, wounds, or other breaks in the skin can become infected.
  • Scratching can damage skin and spread bacteria between lesions.
  • Limited access to regular hygiene can make bacterial spread more likely.
  • Crowded living conditions can increase close contact and the sharing of contaminated items.

Complications

Ecthyma Complications

  • Ulcers may persist or take longer to close.
  • Scarring or lasting changes in skin color may occur after healing.
  • Cellulitis can develop when infection spreads into deeper surrounding skin.
  • Lymphangitis can cause inflammation along the lymph vessels.
  • An abscess, or pocket of pus, may form.
  • Rarely, bacteria can enter the bloodstream and cause a serious systemic infection.

RARE BUT SERIOUS

Ecthyma gangrenosum is not ordinary ecthyma

Ecthyma gangrenosum causes rapidly worsening necrotic lesions and is usually associated with severe systemic infection or significant immunosuppression. It requires urgent medical evaluation. It is also different from pyoderma gangrenosum, an inflammatory condition; the two names should not be used interchangeably.

Diagnosis

How Ecthyma Is Diagnosed

A clinician usually diagnoses ecthyma by examining the sores, their crusts, depth, location, progression, and the surrounding skin. The appearance and history often provide enough information to identify the infection and distinguish it from more superficial impetigo.

When a skin swab or culture may be needed

A skin swab or bacterial culture may be needed for recurrent, extensive, treatment-resistant, or atypical lesions. Additional tests may be considered if sores are rapidly becoming necrotic, the person is very unwell, or an abscess, pyoderma gangrenosum, another ulcerating condition, or ecthyma gangrenosum is possible. Routine ecthyma testing does not imply that Pseudomonas is the cause; that organism is more specifically associated with ecthyma gangrenosum.

Treatment & Management

Ecthyma Treatment and Management

  • Gently clean the lesions as directed by a clinician.
  • Follow medical instructions for loosening or removing loose crusts.
  • Apply prescribed medicine exactly as directed.
  • Keep sores covered with clean dressings when advised.
  • Wash your hands after touching a lesion or changing a dressing.
  • Avoid sharing towels, clothing, or bedding while sores are active.

Antibiotics depend on the extent and severity

Topical antibiotics may be used for limited disease, while oral or intravenous antibiotics may be needed for multiple, deep, spreading, or systemic infections. Treatment should be selected by a clinician based on the suspected bacteria, local resistance patterns, culture results when available, allergies, and overall health. Suspected ecthyma gangrenosum requires urgent hospital evaluation and targeted treatment; ecthyma gangrenosum treatment is not the same as routine ecthyma treatment.

Prevention

How to Prevent Ecthyma

  • Wash your hands regularly, especially after touching sores or changing dressings.
  • Keep cuts and other wounds clean and covered.
  • Avoid scratching infected areas.
  • Do not share towels, razors, clothing, or bedding.
  • Wash clothing, towels, and linens that may have touched infected skin.
  • Seek care for infected eczema or scabies.

Preventing and treating skin breaks, controlling eczema, managing diabetes when applicable, and completing prescribed antibiotics can lower the chance of recurrence and spread. These steps also help reduce the risk of both impetigo and ecthyma among household members.

Outlook and Prognosis

Ecthyma Outlook and Prognosis

Most uncomplicated cases improve with appropriate treatment. Because ecthyma forms deeper ulcers, healing may take longer than with ordinary impetigo, and scars or temporary changes in skin color may remain. Prompt ecthyma treatment and management of contributing skin problems can improve recovery.

  • Delayed treatment can allow the infection to become deeper or spread.
  • Diabetes may slow healing or increase the risk of complications.
  • Poor circulation can reduce the supply of oxygen and nutrients needed for repair.
  • Immune suppression can make infection harder to control.
  • Extensive disease may require longer or more intensive treatment.
  • Ongoing eczema or scratching can delay healing and contribute to recurrence.

When Should You See a Doctor

When Should You See a Doctor for Ecthyma?

SEEK URGENT CARE

Watch for signs of severe infection

Seek urgent care for rapidly spreading redness or swelling, severe pain, fever, confusion, weakness, red streaks, black or purple skin, or rapidly worsening necrotic sores. These warning signs are especially important in someone who is immunocompromised and may indicate a serious infection such as ecthyma gangrenosum.

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