Systemic Mycoses
Aspergillus, a systemic mycosis, produces cutaneous ulcers most often by direct implantation following trauma, and much less commonly, following dissemination from a primary pulmonary tract infection. The lesion begins as a papule, evolving into an ulcer. The rate and extent of ulcer enlargement depend largely upon the degree of immunosuppresion. Patients with large, rapidly progressive ulcers typically have severe underlying disease states, such as AIDS, neutropenia, or functional neutrophil defects. These ulcers can take on the appearance of ecthyma gangrenosum.
Zygomycetes (mucormycosis) is a class of fungi capable of causing a variety of systemic infections in humans. Cutaneous infections are usually the result of direct inoculation into the skin and are almost always associated with trauma or wounds. In some cases, the trauma may seem trivial, such as an intravenous catheter insertion or insulin injection site. Patients with mucormycosis typically have serious, underlying immune disorders or challenges, such as diabetes mellitus, organ transplantation, or neutropenia. Infection in these hosts typically begins as a single, painful, indurated area of cellulitis, progressing to ulceration. It may take on the appearance of ecthyma gangrenosum . Infection can also occur in large traumatic wounds or burns, when associated with contaminated dressings or splints. In such cases, the infection appears as an ischemic tissue infarction.
Differential Diagnosis: Mycotic infections can be distinguished from cutaneous anthrax in the following manner.
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Mycotic infections |
Cutaneous anthrax |
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*Lesion is localized in a prior burn site, wound, or injury, possibly trivial *Patient has AIDS, severe neutropenia, or functional neutrophil defects *Patient has poorly controlled diabetes, neutropenia, or renal disease *Infection is associated with contaminated dressing or splints *Ulcers are painful |
*Patient has no underlying immune deficiency *Ulcer is painless *Ulcer and eschar are surrounded by characteristic non-pitting edema |
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