Ecthyma - Symptoms, Causes & Treatment
Medically reviewed by Dr. Anand S. Urhekar, MD, MD Pathology, Clinical Advisor · Last updated July 2026
A deep form of impetigo in which streptococcal or staphylococcal infection extends into the dermis, creating punched-out ulcers with thick adherent crusts and a raised violet edge. It usually affects the lower legs and buttocks and heals with scarring.
Concerned this might be ecthyma? Scan it with our AI skin checker or, for moles and pigmented spots, our AI mole checker. Free, no signup required.
Quick Answer
Ecthyma is deep impetigo: a bacterial infection that ulcerates into the dermis, forming punched-out sores with thick, hard crusts on the legs or buttocks. Unlike superficial impetigo it scars. Risk factors include poor hygiene, insect bites, malnutrition, diabetes and immunosuppression. Treatment requires oral antibiotics such as flucloxacillin, plus wound care — topical treatment alone is not enough.
Symptoms
- Punched-out ulcers 0.5–3 cm across
- Thick, adherent yellow-grey crust
- Raised violet or red border
- Usually on lower legs, thighs or buttocks
- Heals slowly with scarring
Causes & Risk Factors
- Streptococcus pyogenes, often with Staphylococcus aureus
- Insect bites, scratches or existing skin damage
- Poor hygiene and crowded living conditions
- Malnutrition, diabetes, immunosuppression
- Warm humid climates
Treatment & Management
- Oral antibiotics (flucloxacillin or a suitable alternative) for 7–10 days
- Soaking and gentle removal of crusts
- Wound dressings and antiseptic cleansing
- Swab for culture in recurrent or non-responding cases
- Treating scabies or insect bites where these are the entry point
When to See a Doctor
See a doctor for any crusted ulcer that is enlarging, painful or accompanied by fever or spreading redness. Ulcers on the legs of people with diabetes or poor circulation need prompt review.
Frequently Asked Questions
Is ecthyma the same as impetigo?
It is the deeper form. Impetigo stays in the epidermis and heals without a scar; ecthyma extends into the dermis, produces ulcers and leaves permanent scarring.
Is it contagious?
Yes. The causative bacteria spread by direct contact and via towels or bedding. Cover lesions, avoid sharing linen and complete the full antibiotic course.
Medical References
Information on this page is sourced from and verified against reputable medical resources:
Concerned About Your Skin?
Upload a photo and get instant AI-powered analysis across 80+ skin conditions. Track your condition over time with photo timelines, or use our dedicated AI mole checker for moles and pigmented lesions.
Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. The content on this page should not be used to diagnose or treat any health problem. Always consult with a qualified healthcare professional for proper medical evaluation, diagnosis, and treatment of your condition.