Mycetoma is a term for a subcutaneous infection caused by either by bacterial (actinomycetes, most important representative being Nocardia sp.) or fungal (eumycetoma) pathogens. The condition is chronic and may be severely debilitating, with main clinical features being development of painless communicating nodules on distal lower extremities.
Mycetoma is most frequently encountered among males between 20-50 years living in countries along the equator. The prevalence is mostly seen in Mexico, Venezuela, Somalia, Senegal, Yemen, Sudan, and India. Inoculation of the organism after trauma is the predominant mode of infection, which is perhaps one of the reasons why the condition is more common among barefoot-walking populations   . Peasants and agriculture workers are at a particular risk for acquiring mycetoma, making occupational factors important in the pathogenesis . A painless, firm mass containing numerous communicating nodules and abscesses is the typical lesion of mycetoma   . The feet are affected in the majority of cases, while hands and the trunk are other potential sites . Nodular communication through the development of fistulas results in the release of a syrup-like purulent or seropurulent discharge that contains grains formed by the causative agent . In some patients, a prolonged infection can lead to dissemination of pathogens into the skeletal system and the systemic circulation, causing bacteremia or even life-threatening sepsis . The clinical course of mycetoma (also know as Madura's foot, named after the Indian endemic region of Madura) is rapid and amputation may be frequently indicated due to the extreme disfiguring of the distal extremities by nodular breakdown .
Entire Body System
A properly obtained patient history containing information about the course of symptoms and occupancy may reveal the possible mode of infection and consequently, the underlying pathogen. Moreover, communicating nodular lesions and syrup-like exudate can be observed during a physical examination, which could be sufficient to make a presumptive diagnosis. In fact, the color of grains can indicate the cause of mycetoma in active phases of the disease - white, yellow or red grains are suggestive of bacterial etiology, while fungal grains are usually black or pale  . To confirm mycetoma, however, several diagnostic procedures should be used :
- Imaging studies - X-rays, computed tomography (CT), ultrasonography, or magnetic resonance imaging (MRI) of the affected limb are necessary for determining the extent of lesions and the damage caused to the musculoskeletal, vascular and subcutaneous tissues  .
- Microbiology - In order to define optimal therapy, identification of the causative agent is imperative and procedures such as fine-needle aspiration cytology (FNAC) or deep-seated biopsy are necessary to obtain a valid sample for an investigation . Subsequent microscopic examination (using various stains) or cultivation using gram and Ziehl-Neelsen (ZN) stains are recommended techniques to discern between eumycetoma and bacterial pathogens. Skin tests using antigens of actinomycetes and serology have shown to be ineffective diagnostic tools, but the use of molecular methods - polymerase chain reaction (PCR), to detect bacterial or fungal DNA in the lesions is demonstrating excellent results. Its availability in general practice, however, is yet to occur, especially in endemic countries  .
Treatment must be continued until the patient is cured. The mean duration of treatment is usually more than one year. [mycetoma.edu.sd]
Management and treatment Medical treatment with sulfones can cure actinomycetic mycetomas, whereas surgery is the main treatment for fungal mycetomas. Prophylaxis consists of disinfecting wounds and wearing shoes. [orpha.net]
Treatment of eumycetoma Reports on the medical treatment of eumycetoma are insufficient and inadequate. [dovepress.com]
However, early detection and treatment are important to reduce morbidity and improve treatment outcomes. [who.int]
What is the best treatment? Mycetoma is a difficult disease to successfully treat. Treatment typically includes both antimicrobial therapy and surgery. Surgery alone is rarely successful. No treatment of choice has been established. [infectiousdiseaseadvisor.com]
Prognosis The prognosis is poor for fungal mycetomas. The documents contained in this web site are presented for information purposes only. [orpha.net]
Prognosis and therapy Mycetomas caused by fungi are usually resistant to chemotherapy , although anecdotal reports of response to long-term therapy with ketoconazole has been appeared [1413, 2403]. [drfungus.org]
Strong clinical suspicion, exact categorization of lesion into eumycotic or actinomycotic along with culture correlation, is essential for prognosis and effective therapy. [ncbi.nlm.nih.gov]
Etiology The agents causing mycetoma are very common saprophytes that are found in the soil and on thorny shrubs in semi-desert climates. [orpha.net]
The etiologic agents range from bacteria to fungi existing free in nature as soil or plant saprophytes gaining entrance into the tissues through abrasion or implantation. Actinomycetoma is caused by aerobic species of actinomycetes. [aspergillus.org.uk]
Complete patients' characteristics and etiological agents are reported in Table 1. In 2 cases, the infection was acquired in India, in 2 in Ethiopia, an in 1 case each in Senegal, Tanzania, Honduras, and Italy. [karger.com]
Abstract Medical treatment of mycetoma depends on its fungal or bacterial etiology. Clinically, these entities share similar features that can confuse diagnosis, causing a lack of therapeutic response due to inappropriate treatment. [ncbi.nlm.nih.gov]
Etiologies included 13 actinomycetomas and 2 eumycetomas. Etiologic agents were Nocardia brasiliensis in 12 cases, Nocardia asteroides in one and Madurella mycetomatis in 2. [journals.lww.com]
Summary Epidemiology Annual incidence is unknown. The condition is endemic in the northern tropical zone and was first described by McGill in the area of Madura (hence the term 'Madura foot') during the last century. [orpha.net]
Eumycetoma and actinomycetoma–an update on causative agents, epidemiology, pathogenesis, diagnostics and therapy. J Eur Acad Dermatol Venereol 2015;29:1873-1883. van de Sande WW. [afwgonline.com]
Report on the Epidemiological Study on Mycetoma at El Andalous Village, The White Nile State. Federal Ministry of Health National Mycetoma Control Programme; nd. [dovepress.com]
In this retrospective study we report epidemiologic, clinical and microbiologic data of mycetoma observed in the General Hospital of Mexico in a 33 year-period (1980 to 2013). [ncbi.nlm.nih.gov]
Hence, paradoxical responses in context other than mycobacterial infection in an immunocompromised host could provide insights into the pathophysiology and the optimal strategy for treatment. [ncbi.nlm.nih.gov]
Pathophysiology The body parts affected most commonly in persons with mycetoma include the foot or lower leg, with infection of the dorsal aspect of the forefoot being typical. [avensonline.org]
European College of Veterinary Pathologists Topics and areas of interest Host-pathogen interactions; Pathophysiology of infectious diseases Barrier crossing / Innate immune defenses Pathogen-endothelium interactions Neuropathology Second-opinion diagnosis [research.pasteur.fr]
The pathophysiology of this disease is not well understood. Some fungi that produce mycetoma also produce melanin, which is a virulence factor for many fungi. Toxins are not produced by the organisms causing mycetoma. [infectiousdiseaseadvisor.com]
Opportunities Elaborating a public health strategy for the prevention and control of Mycetoma requires collection of epidemiological data on burden of disease, investment in research and product development, so that cost-effective prevention, diagnosis [who.int]
Health care providers and researchers believe that wearing shoes might prevent injuries that can lead to mycetoma. [cdc.gov]
Limb amputation to prevent potentially fatal severe secondary bacterial infections may be needed in advanced cases. The following is an English-language resource that may be useful. [msdmanuals.com]
- Welsh O, Al-Abdely HM, Salinas-Carmona MC, et al. Mycetoma Medical Therapy. PLoS Negl Trop Dis. 2014;8(10):e3218
- Venkatswami S, Sankarasubramanian A, Subramanyam S. The madura foot: looking deep. Int J Low Extrem Wounds. 2012;11(1):31-42.
- Bonifaz A, Tirado-Sánchez A, Calderón L, et al. Mycetoma: experience of 482 cases in a single center in Mexico. PLoS Negl Trop Dis. 2014;8(8):e3102.
- Suleiman SH, Wadaella ES, Fahal AH. The Surgical Treatment of Mycetoma. Wanke B, ed. PLoS Negl Trop Dis. 2016;10(6):e0004690.
- Hemalata M, Prasad S, Venkatesh K, et al. Cytological diagnosis of actinomycosis and eumycetoma: a report of two cases. Diagn Cytopathol. 2010;38(12):918-920.
- van de Sande WW, Fahal AH, Goodfellow M, et al. Merits and pitfalls of currently used diagnostic tools in mycetoma. PLoS Negl Trop Dis. 2014; 8(7):e2918.