Ecthyma

Key Points
Similar to Impetigo, but deeper in the tissue
Skin infection characterized by sores with ulcers underneath
Most commonly affects the buttocks, thighs, legs, ankle and feet

Ecthyma is a variation of Impetigo, presenting at a deeper level of tissue. It is a skin infection characterized by crusted sores beneath which ulcers form. The same bacteria (Streptococcus pyogenes and/or Staphylococcus aureus ) that causes Impetigo is responsible for Ecthyma, but it causes deeper erosions of the skin. It affects people of all ages, sex and race equally, though the infection may be deeper in children, the elderly, and those with compromised immunity. People with poor hygiene or who live in crowded living conditions or tropical places are at a higher risk for infection. Moreover, untreated Impetigo may also develop into Ecthyma.

Ecthyma lesions usually begin as small blisters or pustule on an inflamed area of skin. A hard crust soon covers this. Underneath, the crust will be an ulcer that may be red, swollen and oozing with pus. Lesions may stay the same size, heal spontaneously, or gradually enlarge. The buttocks, thighs, legs, ankle and feet are the most common areas affected, though in some cases, the local lymph nodes become swollen and painful.

Differential Diagnosis (Other conditions with similar appearance)

Cutaneous Anthrax
Pseudomonas bacteremia

Diagnosis
Key Points
Clinical evaluation

Diagnosis is determined by clinical evaluation and should be recognized by a professional dermatologist based on characteristic appearance. Cultures of lesions are indicated only when the patient does not respond to treatment. Patients with recurrent Impetigo should also have nasal culture.

Treatment
Topical Mupirocin or Retapamulin
Oral antibiotics

Treatment depends on the extent and severity of infection. Any underlying disease or skin infection such as Scabies or Dermatitis should also be treated. Crusted areas should be soaked in a mixture of water and white vinegar several times a day. Topical antibiotic ointment such as Mupirocin may be prescribed and applied three times a day to the affected areas.

In some cases, oral antibiotics, such as Penicillin, are prescribed for several weeks if the infection is extensive or proving slow to respond to topical antibiotics. Good hygiene is important for management of Ecthyma. Wash the areas daily and change and launder clothes routinely.