What is ecthyma?
Ecthyma is a skin infection characterised by crusted sores beneath which ulcers form. It is a deep form of impetigo as the same bacteria causing the infection are involved but ecthyma causes deeper erosions of the skin.
Ecthyma with scarring
Who gets ecthyma?
People of all ages, sex and race can be affected, although children, elderly people and immunocompromised patients (e.g. diabetes, neutropenia, immunosuppressive medication, malignancy, HIV) tend to have a greater chance of infection. Other factors that increase the risk of ecthyma include:
- Poor hygiene and crowded living conditions
- High temperature and humidity, e.g. tropical places
- Presence of minor injuries or other skin conditions such as scratches, insect bites or dermatitis
- Untreated impetigo, particularly in patients with poor hygiene.
What are the signs and symptoms?
Ecthyma lesion usually begins as a vesicle (small blister) or pustule on an inflamed area of skin. A hard crust that is harder and thicker than the crust of impetigo soon covers this. With difficulty, the crust can be removed to reveal an indurated ulcer that may be red, swollen and oozing with pus. Lesions may stay fixed in size and sometimes resolve spontaneously without treatment, or they may gradually enlarge to a sore of 0.5-3 cm in diameter.
The areas most affected are the buttocks, thighs, legs, ankle and feet. Occasionally, the local lymph nodes become swollen and painful.
What treatment is available?
Treatment depends on the extent and severity of infection. Any underlying disease or skin infection such as scabies or dermatitis should also be treated.
- Soak crusted areas
Soak a clean cloth in a mixture of half a cup of white vinegar in a litre of tepid water. Apply the compress to moist areas for about ten minutes several times a day. Gently wipe off the crusts.
- Topical antiseptics or antibiotics
A topical antibiotic ointment such as fusidic acid or mupirocin is often prescribed for localised ecthyma. A topical antiseptic such as povidone iodine, antibacterial Manuka honey or hydrogen peroxide cream may be used instead. Apply it at least three times a day to the affected areas and surrounding skin. The treatment should be applied after removing crusts. Look carefully for new lesions to treat. Continue for several days after healing.
- Oral antibiotics
Oral antibiotics are recommended if the infection is extensive or proving slow to respond to topical antibiotics. The preferred antibiotic is a penicillin, however the antibiotic chosen should be active against both Streptococcus pyogenes and Staphylococcus aureus (usually dicloxacillin or flucloxacillin). The duration of treatment varies; several weeks of therapy may be necessary to completely resolve ecthyma.
Another very important factor to consider in the overall management of ecthyma is to improve hygiene. Measures to take include:
- Washing daily with antiseptic soap or cleanser
- Changing and laundering clothes and linen frequently
- Using separate towels and flannels to prevent spreading infection.
- Textbook of Dermatology. Ed Rook A, Wilkinson DS, Ebling FJB, Champion RH, Burton JL. Fourth edition. Blackwell Scientific Publications.
On DermNet NZ:
- Bacterial skin infections
- Staphylococcal skin infections
- Streptococcal skin infections
- MRSA (Methicillin resistant Staphylococcus aureus)
- Necrotising fasciitis
- Ecthyma gangrenosum (pseudomonas infection)
- Ecthyma – Medscape Reference
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