Cutaneous zygomycosis
Introduction
The term zygomycosis can be applied to 2 conditions: one caused by opportunistic fungi of the order of Mucorales and another caused by primary pathogenic fungi of the order of Entomophtorales.1., 2., 3. This contribution addresses only the former.
Zygomycosis, also known as mucormycosis (because of its taxonomy), is caused by a group of opportunistic fungi of the class of Zygomycetes, characterized by acute rhinocerebral and pulmonary episodes with vascular involvement, thrombosis, and infarctions.3,4., 5., 6. It occurs mainly in uncontrolled diabetic patients and in immunosuppressed individuals. Its clinical varieties are rhinocerebral (the most frequent), pulmonary, cutaneous, gastrointestinal, disseminated, and miscellaneous.2., 5.
Cutaneous zygomycosis has 2 forms: primary cutaneous and secondary cutaneous. Primary cutaneous, which starts with various types of trauma, is frequent in immunosuppressed patients and has a good prognosis when diagnosed early. Secondary cutaneous zygomycosis, which is usually a dissemination to the skin from a rhinocerebral location, occurs more frequently in uncontrolled diabetic patients and immunocompromised individuals, being a severe invasive entity with a poor prognosis.3., 7., 8.
Section snippets
Etiology
The disease is caused by various Zygomycetes of the order of Mucorales, including several families, among which Mucoraceae is predominant. The most frequently isolated genera are Rhizopus, Mucor, and Lichtheimia (previously Absidia), and to a lesser extent Rhizomucor, Mortierella, Saksenaea, Syncephalastrum, Cunninghamella, and Apophysomyces.3., 9., 10. The most frequently reported genus is Rhizopus. At the cutaneous level, the most frequently reported species is Rhizopus oryzae in 47% to 85%
Epidemiology
Zygomycosis is a cosmopolitan disease. It is a rare entity that has experienced a significant increase in the past 2 decades. Some authors consider it the third most frequent opportunistic mycosis, after candidiosis and aspergillosis. There are 1.7 cases per million per year in the United States with an estimate of 500 new cases per year.15 In a pathologic analysis,5 1 to 5 cases per 100,000 autopsies were reported. There are no precise data from Latin American countries, but some tertiary-care
Pathogenesis
The onset of this disease is becoming increasingly clear. The disruption of defense mechanisms is extremely important, particularly neutrophil and macrophage activity. The presence of serum iron ions (Fe2+) is of vital importance, as, under normal conditions, they are taken up by serum proteins, but due to the acidity of the medium, particularly in cases of diabetic ketoacidosis or metabolic acidosis, iron ions are dissociated and are a clear stimulus for the development of mucorales.3., 5.
In
Primary cutaneous zygomycosis
Primary cutaneous zygomycosis is a relatively rare cutaneous and subcutaneous disease that accounts for 7% to 15% of all reported cases of zygomycoses.11 It starts after fungal inoculation caused by contaminated elastic or adhesive tape at catheter or venipuncture sites in severely immunosuppressed patients. Most cases are in patients with acute and chronic leukemia with acute lymphoblastic leukemia being the most frequent. It has no specific location, but has been observed on the arms, legs,
Laboratory diagnosis
One of the first studies performed is direct potassium hydroxide (KOH) examination of the exudates, nasal discharge, and macerated biopsies. The specimen should be cleared with 10% to 20% KOH. Under the microscope, one can see numerous coenocytic (nonseptated), hyaline, bifurcated hyphae, 5 μm wide by 20 to 50 μm long. The etiologic agent is confirmed by means of (repeated) cultures in Sabouraud dextrose agar and potato dextrose agar. Specimens should not be seeded in Sabouraud media with
Treatment
In general, treatment success depends on a prompt diagnosis, resolution of associated factors, the patient's condition, and the promptness in starting therapy.5., 41.
Prophylaxis
The most important aspect of treatment is the control of comorbidities, such as diabetes stabilization and control, the return to normal immune status, as well as immunosuppressive therapies (immunosuppressors, steroids, deferoxamine).
The recommended prophylactic measures for diabetic and uncontrolled patients or those with hematologic conditions, such as leukemia and lymphoma, are those used in any immunocompromised patient: isolation in sterile areas, closely supervised clinical management,
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