Publish date: Posted on
Last updated: February 17, 2024
Keywords #
ecthyma,
ecthymatous impetigo
Diagnosis #
Ecthyma is an infectious process in which S. aureus and/or S. pyogenes form cutaneous ulcers[2].It can follow untreated impetigo, trauma, or an arthropod bite occluded by footwear or clothing [4]. The ulcers penetrate the dermis and if untreated enlarge to 3cm or more over the course of weeks to months and often heal with scarring [2].
Key Concepts #
- Ecthyma is an infectious process caused by S. aureus, S. pyogenes, or both.
- Has a predilection for the lower extremities.
- Requires treatment with systemic antibiotics.
- Complications of cutaneous S. pyogenes infections include rheumatic fever and post-streptococcal glomerulonephritis.
Epidemiology #
Risk factors include immunosuppression, malnutrition, diabetes, poor hygiene and humidity [2,4]. Has been noted among military recruits and persons in overcrowded conditions. More common in the extremes of age, particularly in neglected elderly patients [2].
Clinical Features #
- Begins as a vesiculopustule with a yellow-gray crust.
- Progresses to ulcers with a punched-out appearance and hemorrhagic crust.
- Thick crust with yellow-grey “oyster shell” appearance may develop.[1]
- The margins of the lesions are raised, violaceous and indurated.[2]
- The base of the ulcer may be necrotic or granulomatous and extends into the dermis.
- May be associated with lymphadenitis or lymphadenopathy. [3]
Differential Diagnoses #
- Ecthyma
- Cutaneous fungal disorders (histoplasmosis, cryptococcosis, sporotrichosis)
- Herpes simplex
- Herpes simplex virus
- Vasculitis
- Bullous pemphigoid
- Orf
- Cutaneous anthrax
- Tularemia
- Rickettsial disease
- Venous stasis ulcer
- Mycobacterium marinum infection
Diagnostic Workup #
Gram stain and culture of exudate from the ulcer is recommended by the IDSA to determine whether S. aureus, S. pyogenes or both are present in order to guide treatment as below. Empiric treatment without workup may be reasonable in a typical case [5].
Treatment #
Oral therapy with a 7-day course of dicloxacillin or cephalexin is recommended as isolates of S. aureus from ecthyma are usually methicillin susceptible. Exceptions include a culture that yields streptococci alone, in which case oral penicillin is preferred. If MRSA is either confirmed or suspected, doxycycline, clindamycin, or sulfamethoxazole-trimethoprim are possible treatment options, but chosen treatment should be dictated by susceptibilities[5].
Slide Viewer #
https://utahderm.med.utah.edu/image-viewer/References #
- Elston, Dirk et al. Infectious Diseases of the Skin. Taylor & Francis Group, 2009. Web.
- Kang, Swon et al. Fitzpatrick’s Dermatology, 9e. McGraw-Hill, 2019. Web.
- Meshkov, Lauren S. et al. Taylor and Kelly’s Dermatology for Skin of Color, 2e. McGraw-Hill, 2016. Web.
- Orbuch, David E. et al. “Ecthyma: a potential mimicker of zoonotic infections in a returning traveler.” International Journal of Infectious Diseases(2014): 178-180. https://doi.org/10.1016/j.ijid.2014.08.014.
- Stevens, Dennis et al. “Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America”. Clinical Infectious Diseases. 2014. https://doi.org/10.1093/cid/ciu296.
