Mycetoma

Mycetoma is a chronic, progressive subcutaneous granulomatous infection caused by fungi (eumycetoma) or bacteria (actinomycetoma), recognized by WHO as a neglected tropical disease since 2016. The pathognomonic triad is a painless subcutaneous mass, sinus tract formation, and discharge containing characteristic grains. [1-2] Over 70 causative organisms have been identified, with Madurella mycetomatis being the most common eumycetoma agent and Nocardia brasiliensis, Actinomadura madurae, and Streptomyces somaliensis the most common actinomycetoma agents. [2-3] No case of spontaneous resolution has ever been reported. [4]

• Onset and mechanism of inoculation: Ask about thorn pricks, splinters, or minor skin trauma — the organism is inoculated through breaches in the skin, typically on body parts in contact with soil [2][4]
• Progression: Begins as a small painless subcutaneous nodule at the inoculation site, slowly enlarging over months to years; time from infection to presentation ranges from 3 months to 50 years [2]
• Sinus tracts and discharge: Ask about draining sinuses with sero-purulent or purulent material; inquire about grain color (black/dark = eumycetoma; white/yellow/red = actinomycetoma, though overlap exists) [2][5]
• Pain: Typically painless or minimally tender ("wooden induration"), though secondary bacterial infection can cause pain; one Ethiopian cohort reported pain in 90.9% of cases, suggesting advanced disease [2][6]
• Functional impairment: Assess for loss of function, restricted joint motion, difficulty walking or working [2][4]
• Prior treatments: Ask about prior antibiotics, antifungals, surgeries, and use of traditional/herbal medicine (>80% of patients in some endemic settings use phytotherapy before seeking care) [5]
• Travel and residence: Residence in or travel to the "mycetoma belt" — Sudan, Mexico, India, Senegal, Chad, Ethiopia, Somalia, Venezuela, Yemen [4][7]

• Bone involvement: Radiographic evidence of bone erosion or destruction — occurs in ~28% of cases and portends worse outcomes, higher amputation risk [2][8]
• Rapid enlargement or spread to contiguous structures (muscle, tendon, joint)
• Lymphatic or hematogenous dissemination — rare but reported [4]
• Secondary bacterial infection with systemic signs (fever, cellulitis, sepsis) [4]
• Head/neck or truncal involvement — exceedingly rare and poses significant diagnostic and therapeutic challenges [9]
• Immunosuppression — increases disease severity score and complicates management [1]
• History of surgical recurrence — positive predictor of amputation (OR 3.67) [10]

Eumycetoma

• First-line: Itraconazole 200 mg BID for ≥12 months, combined with surgical excision [2][11]
• Alternative/emerging: Fosravuconazole 200 mg once weekly — comparable efficacy to itraconazole with advantages of weekly dosing, no food requirement, and fewer drug interactions [4]
• Voriconazole and posaconazole have shown promise in refractory cases [2]
• Terbinafine has limited efficacy [2]
• Ketoconazole — historically used but restricted/withdrawn by FDA and EMA due to hepatic toxicity and adrenal suppression [2]
• Amphotericin B has poor in vitro activity; echinocandins have no activity against M. mycetomatis [2]

Actinomycetoma

• First-line: Co-trimoxazole (TMP-SMX) 48 mg/kg/day in 5-week cycles + amikacin 15 mg/kg/day divided q12h for 3 weeks of each cycle; cure rates up to ~90% [1-2]
• Alternatives: Co-amoxiclav (if co-trimoxazole allergy); netilmicin (if amikacin allergy); amikacin + carbapenem (imipenem/meropenem) for refractory cases [2]
• Rifampicin + TMP-SMX has shown efficacy in refractory/atypical cases [9]

Medication cautions

• Amikacin requires renal and audiometric monitoring during the 2-week interval of each cycle [2]
• Itraconazole requires liver function monitoring with prolonged use [12]
• Co-amoxiclav alone may develop acquired resistance and is generally not effective against A. madurae [2]

• No specific dietary triggers or restrictions are directly associated with mycetoma
• Itraconazole absorption is significantly enhanced when taken with food (capsule formulation) — counsel patients accordingly [4]
• Fosravuconazole can be taken without food, which is an advantage in resource-limited settings [4]
• Adequate nutrition supports immune function and wound healing during prolonged treatment courses

• Musculoskeletal: Joint stiffness, restricted range of motion, limb deformity
• Skin: Other nodules, draining sinuses elsewhere, satellite lesions
• Constitutional: Fever (suggests secondary bacterial infection), weight loss
• Lymphatic: Regional lymphadenopathy
• Neuropsychiatric: Depression, social stigma, psychosocial impact — common and underrecognized [4]
• Functional: Ability to perform activities of daily living, work capacity, school attendance [4]

• Occupational history: Farming, manual labor, pastoralism — strong association with barefoot outdoor work [4][13]
• Footwear use: Walking barefoot is a major risk factor [7]
• Community context: Awareness of mycetoma in the community is often poor; 96% of surveyed villagers in one endemic Sudanese village had poor knowledge [2]
• No hereditary component has been identified; no animal reservoir confirmed, though rare cases in vertebrates have been reported [7]
• Social history: Assess for stigma, isolation, economic impact — patients may drop out of school or be unable to work [4]

• Male sex — male:female ratio approximately 2.5–3:1 [5][13]
• Age 15–45 years (peak 20–30 years) [4][13]
• Rural residence — 73% of cases [13]
• Agricultural/pastoral occupation — farmers and pastoralists are most commonly affected [6][13]
• Walking barefoot or inadequate protective clothing [7]
• Residence in the mycetoma belt: Tropical/subtropical regions with hot, dry climate and short rainy season — Sudan, India, Mexico, Senegal, Ethiopia, Somalia, Chad [7]
• Immunosuppression — increases severity [1]
• Prior surgical recurrence — increases amputation risk [10]

The differential depends on the stage and presentation: [2]

• Early lesions (subcutaneous mass without sinuses):
  • Foreign body granuloma — history of penetrating injury
  • Kaposi sarcoma — violaceous plaques/nodules, HIV association
  • Fibroma / neurofibroma / fibrolipoma — non-inflammatory, no discharge
  • Malignant melanoma — pigmented, irregular borders
  • Sporotrichosis — lymphocutaneous spread pattern, rose gardener exposure
• Large lesions / advanced disease:
  • Osteosarcoma / rhabdomyosarcoma — rapidly growing, imaging distinguishes
  • Chronic osteomyelitis — fever, elevated inflammatory markers
  • Tuberculosis (cutaneous/osseous) — PPD/IGRA, AFB stain
  • Atypical mycobacterial infection — culture, biopsy
  • Botryomycosis — bacterial granules but caused by common bacteria (Staph, Pseudomonas)
• Actinomycetoma-specific mimics (Latin America):
  • Paracoccidioidomycosis, lobomycosis, phaeohyphomycosis[2]

Key distinguishing feature: The presence of grains in discharge is pathognomonic for mycetoma and distinguishes it from most mimics. [2]

• Previous episodes of mycetoma or recurrence (recurrence rate ~10–27.5%) [7-8]
• Prior surgical excisions — incomplete excision without antimicrobial therapy has up to 90% recurrence [12]
• Immunosuppressive conditions (HIV, diabetes, immunosuppressive medications)
• Chronic skin conditions or prior skin trauma at the affected site
• Hepatic or renal disease — impacts drug selection and monitoring

• Inspection: Firm, "woody" subcutaneous mass; multiple sinus tracts with sero-purulent discharge; grain color and consistency (black grains suggest eumycetoma; white/yellow/red grains suggest actinomycetoma) [2]
• Palpation: Non-tender or minimally tender induration; assess for fluctuance (secondary abscess), crepitus (bone involvement)
• Size and extent: Measure lesion dimensions; assess for satellite lesions
• Joint/limb function: Range of motion, motor impairment, deformity
• Lymph nodes: Regional lymphadenopathy [1]
• Atypical presentations: Mycetoma can present without sinus tracts — a high index of suspicion is needed in endemic settings [8][14]
• Vital signs: Usually normal unless secondary bacterial infection is present

• Grain examination: Express grains from sinuses or obtain via fine needle aspiration; deep-seated grains preferred over extruded ones (less contamination, more viable) [2]
  • [2]
• Culture: Plate grains on appropriate media; incubate ≥4 weeks; culture yield is low, especially for actinomycetoma (~27%) [2][8]
• Histopathology: Deep biopsy with H&E stain reliably distinguishes fungal from bacterial etiology; Grocott stain highlights fungal hyphae [2][8]
• Molecular methods: PCR and molecular sequencing — increasingly important for species-level identification, especially in culture-negative cases [3][15]
• Baseline labs for treatment monitoring: LFTs (itraconazole hepatotoxicity), renal function and audiometry (amikacin nephro/ototoxicity) [2][12]
• CBC, ESR/CRP: Non-specific but may be elevated with secondary infection

• Plain radiography (first-line): Assess for soft tissue swelling, periosteal reaction, cortical erosion, bone cavities; changes seen in ~66% of advanced cases [16-17]
• Ultrasound: Useful for identifying grain-containing cavities, guiding aspiration, and assessing lesion extent; more accessible in resource-limited settings [17]
• MRI (gold standard for extent): The "dot-in-circle" sign is highly characteristic — small hyperintense dots (grains) within hypointense spherical lesions on T2-weighted images; seen in 8/9 MRIs in one series. MRI best delineates soft tissue extent, bone involvement, and surgical planning [16-17]
• CT: Useful for bone involvement assessment; shows soft tissue swelling and bone erosion [14][17]
• Imaging is unnecessary for very early, small, superficial lesions where clinical and grain examination suffice

• Grain color and morphology analysis: Size, shape, color, and consistency provide initial clues to the causative organism [2]
• Calcofluor white stain: Fluorescent staining of fungal hyphae [2]
• Ziehl-Neelsen stain: Identifies Nocardia species in actinomycetoma [9]
• MALDI-TOF mass spectrometry: Protein-based identification of causative organisms [15]
• PCR with species-specific or pan-actinomycetes primers: Rapid molecular confirmation [14-15]
• Mycetoma Activity and Severity Clinical Scale (MASS): A recently developed scoring system (severity scale max 24, activity scale max 10) for standardized clinical assessment, though inter-rater reliability remains limited [1]

• Not routinely indicated for mycetoma itself
• Consider baseline ECG if initiating itraconazole (QT prolongation risk, especially with concomitant QT-prolonging drugs) or amikacin (electrolyte monitoring)

Mycetoma is a chronic, non-self-resolving subcutaneous infection that requires prolonged treatment. Key assessment points:

• Distinguish eumycetoma from actinomycetoma — treatment differs fundamentally (antifungal vs. antibacterial) [2-3]
• Actinomycetoma is more aggressive and invades bone earlier but responds better to treatment (cure rates up to 90%) [1-2]
• Eumycetoma has a more indolent course but much lower cure rates (25–75% depending on regimen and lesion size) and higher amputation rates [1][7]
• Small lesion size and good follow-up are the strongest positive predictors of cure (OR 10.09 and 6.81, respectively) [10]
• Complications: Bone destruction, permanent disability, deformity, secondary bacterial infection, lymphatic/hematogenous spread (rare), amputation (3–15%), therapy dropout (~55%), recurrence (~10–27.5%) [7-8]

Eumycetoma

• Medical: Itraconazole 400 mg/day (200 mg BID) for ≥12 months pre-operatively [11-12]
  • [4]
• Surgical: Excision of remaining mass after medical therapy; postoperative antifungal therapy is mandatory to reduce recurrence [7][12]
• Surgery without adequate chemotherapy has recurrence rates up to 90% [12]
• Advanced/refractory cases: Consider voriconazole or posaconazole [2]
• Amputation reserved for advanced, unresponsive disease

Actinomycetoma

• First-line: Co-trimoxazole 48 mg/kg/day (5-week cycles) + amikacin 15 mg/kg/day divided q12h (3 weeks on, 2 weeks off per cycle); up to 4 cycles [2]
• Surgery is rarely needed [2]
• Refractory cases: Amikacin + carbapenem (imipenem/meropenem); check MICs due to resistant strains [2]
• Alternative regimens: Rifampicin + TMP-SMX for Nocardia species [9]

Monitoring during treatment

• LFTs every 1–3 months (itraconazole) [12]
• Renal function and audiometry during amikacin-free intervals [2]
• Clinical and imaging reassessment of lesion size and activity

• Outpatient management is appropriate for most cases — treatment is prolonged (months to years) and primarily oral
• Admission criteria:
  • Secondary bacterial sepsis or severe cellulitis
  • Surgical excision or debridement under general anesthesia
  • Initiation of IV amikacin cycles for actinomycetoma
  • Advanced disease requiring amputation
• Specialist consultation triggers:
  • Infectious disease — for organism identification and antimicrobial guidance
  • Orthopedic/plastic surgery — for surgical planning, especially with bone involvement
  • Dermatology — for biopsy and histopathological assessment
  • Tropical medicine — in non-endemic settings where clinical familiarity is limited

• Follow-up timing: Regular visits every 4–6 weeks during active treatment; clinical and imaging reassessment at 3–6 month intervals to evaluate response [10]
• Treatment duration: Minimum 12 months for eumycetoma; actinomycetoma typically requires multiple 5-week cycles (up to 4+) [2][7]
• Return precautions — seek immediate reassessment for:
  • Rapid increase in mass size or new sinus formation
  • Fever, spreading erythema, or purulent drainage (secondary infection)
  • New bone pain or joint dysfunction
  • Medication side effects: jaundice, dark urine (hepatotoxicity), hearing changes or decreased urine output (amikacin toxicity)
• Expected recovery: Slow; even with optimal therapy, eumycetoma cure rates are modest (25–75%) and recurrence is common. Small lesions treated early have the best outcomes [1][7][10]
• Prevention counseling: Wear protective footwear and clothing during outdoor/agricultural work; avoid walking barefoot in endemic areas [3][7]

1. Development of the Mycetoma Activity and Severity Clinical Scale (MASS): An International Delphi Study. — Chandler DJ, Davey G, Hay RJ, Fahal A, Mycetoma Activity and Severity clinical Scale (MASS) expert panel. The Lancet. Infectious Diseases. 2025.

2. Mycetoma: A Unique Neglected Tropical Disease. — Zijlstra EE, van de Sande WWJ, Welsh O, et al. The Lancet. Infectious Diseases. 2016.

3. Mycetoma: Reviewing a Neglected Disease. — Verma P, Jha A. Clinical and Experimental Dermatology. 2019.

4. Two Dose Levels of Once-Weekly Fosravuconazole Versus Daily Itraconazole in Combination With Surgery in Patients With Eumycetoma in Sudan: A Randomised, Double-Blind, Phase 2, Proof-of-Concept Superiority Trial. — Fahal AH, Ahmed ES, Bakhiet SM, et al. The Lancet. Infectious Diseases. 2024.

5. Mycetoma Epidemiology, Diagnosis Management, and Outcome in Three Hospital Centres in Senegal From 2008 to 2018. — Sow D, Ndiaye M, Sarr L, et al. PloS One. 2020.

6. Mycetoma as a Major Cause of Limb Amputation in Northeastern Ethiopia: A Facility-Based Retrospective Study. — Enbiale W, Nyaoke B, Bekele A, Mohammed KA, Bedane D. PLoS Neglected Tropical Diseases. 2026.

7. Neglected Endemic Mycoses. — Queiroz-Telles F, Fahal AH, Falci DR, et al. The Lancet. Infectious Diseases. 2017.

8. Clinical Presentation, Etiology, and Treatment Outcomes of Mycetoma: A 25-Year Retrospective Study in Southern Thailand. — Chittrakarn S, Kanchanasuwan S, Sangkakul N, Tongsengkee N. PLoS Neglected Tropical Diseases. 2026.

9. Successful Management of Progressive Mycetoma Affecting the Head and Neck. — Sokunbi AE, Osaigbovo II. The American Journal of Tropical Medicine and Hygiene. 2026.

10. Mycetoma Management and Clinical Outcomes: The Mycetoma Research Center Experience. — Musa EA, Abdoon IH, Bakhiet SM, et al. Transactions of the Royal Society of Tropical Medicine and Hygiene. 2023.

11. Eumycetoma and Actinomycetoma--an Update on Causative Agents, Epidemiology, Pathogenesis, Diagnostics and Therapy. — Nenoff P, van de Sande WW, Fahal AH, Reinel D, Schöfer H. Journal of the European Academy of Dermatology and Venereology : JEADV. 2015.

12. Mycetoma Caused by Madurella Mycetomatis: A Neglected Infectious Burden. — Ahmed AO, van Leeuwen W, Fahal A, et al. The Lancet. Infectious Diseases. 2004.

13. Global Sociodemographic, Clinical, and Epidemiological Profiling of Patients With Mycetoma: A Systematic Review. — Salah ME, Fearon Scales ML, Habib K, et al. PLoS Neglected Tropical Diseases. 2025.

14. A Rare Presentation of Actinomycotic Mycetoma of the Hand: A Case Report. — Layegh Mirhosseyni S, Abdi A, Kord M, Ahmadikia K, Alavi Darazam I. BMC Infectious Diseases. 2026.

15. The Developed Molecular Biological Identification Tools for Mycetoma Causative Agents: An Update. — Siddig EE, Verbon A, Bakhiet S, Fahal AH, van de Sande WWJ. Acta Tropica. 2022.

16. Clinical Triad With Multi-Biopsy Histopathology as a Reliable Diagnostic Marker of Mycetomas: A Retrospective Review From a Tertiary Care Center. — Ansari F, Singh S, Bhardwaj A, et al. International Journal of Dermatology. 2023.

17. Mycetoma Imaging: The Best Practice. — Bahar ME, Bakheet OELH, Fahal AH. Transactions of the Royal Society of Tropical Medicine and Hygiene. 2021.