• Symptoms

    The main symptom of ecthyma is a small blister with a red border that may be filled with pus. The blister is similar to that seen in persons with impetigo, but the infection spreads much deeper into the skin.

    After the blister goes away, a crusty ulcer appears.

    Signs and tests

    Your doctor can usually diagnose this condition simply by looking at your skin. In rare cases, the fluid inside the blister may be sent to a lab for closer examination or a skin biopsy may be done.