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. Ecthyma causes deeper erosions of the skin into the dermis.
Who gets ecthyma?
People of all ages, sex and race can be affected, although children, elderly people and immunocompromised patients (eg 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, eg 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 of ecthyma?
Ecthyma most often affects buttocks, thighs, legs, ankle and feet. Occasionally, the local lymph nodes become swollen and painful.
Ecthyma lesion usually begins as a vesicle (small blister) or pustule on an inflamed area of skin.
- A hard crust soon covers the blister.
- 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.
- They resolve slowly leaving a scar.
Complications of ecthyma
Complications of ecthyma may include:
- More widespread infection: cellulitis,erysipelas, lymphangitis, gangrene, lymphadenitis, and bacteraemia
- Permanent scarring
- Rarely, post-streptococcal glomerulonephritis
What is the treatment for ecthyma?
- 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 antibiotic of choice is a penicillin, usually dicloxacillin or flucloxacillin, which are active against both Streptococcus pyogenes and Staphylococcus aureus. 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.
- Use nets and repellent sprays to prevent insect bites.
- Reduce scratching at insect bites, chickenpox blisters and scabies by applying calamine lotion, colloidal oatmeal or baking soda.
- Ecthyma; Lippincott's Guide to Infectious Diseases. Lippincott Williams & Wilkins, 2011
- Textbook of Dermatology. Ed Rook A, Wilkinson DS, Ebling FJB, Champion RH, Burton JL. Fourth edition. Blackwell Scientific Publications.
- Insect bites and stings: First aid Mayo Clinic Patient Care and Health Info
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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