Ecthyma is a skin infection with loss of the top layers of the skin caused by necrosis The most common cause of ecthyma in children is GAS and typically presents with painful crusts and erosions ( Fig 66.5 ) Ecthyma gangrenosum is a term typically reserved for a pseudomonas infection that presents with a painful purple papule or nodule that quickly ulcerates with expanding redness Pseudomonas ecthyma should not occur in normal hosts so if the diagnosis is made, the patient requires a workup for potential malignancy or other immunosuppression Other bacteria and opportunistic fungi may cause lesions of ecthyma in immunosuppressed children Therefore, culture is vital to establish a diagnosis Therapy should be guided by cultures but empiric broad-spectrum gram-positive and gramnegative coverage should be started immediately for suspected ecthyma gangrenosum in immunosuppressed patients Consideration should also be given to starting an antifungal agent such as amphotericin and doublecovering pseudomonas, depending on the degree of immunosuppression and the patient’s overall clinical appearance