Mycetoma Clinical Presentation

Updated: Jan 09, 2017
  • Author: Folusakin O Ayoade, MD; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Presentation

History

The classic clinical triad of mycetoma is tumor or soft tissue swelling, sinus tracts, and characteristic macroscopic grains. The grains typically represent aggregates of the infecting organisms. The earliest sign is often painless subcutaneous swelling. Some patients may give a history of a penetrating injury at the site of involvement.

Several years later, a painless subcutaneous nodule is observed. After some years, massive swelling of the area occurs, with induration, skin rupture, and sinus tract formation.

As the infection spreads to contiguous body parts, old sinuses close and new ones open.

Nearly 20% of patients with mycetoma experience associated pain, usually due to secondary bacterial infection or, less commonly, bone invasion.

Constitutional symptoms and signs of mycetoma are rare.

Patients may report a deep itching sensation.

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Physical

Irrespective of the causal agent, the appearance of the mycetoma lesion is consistent, as follows:

  • Initially, subcutaneous swelling is present.

  • In a later phase, a subcutaneous nodule develops.

  • Eventually, massive swelling with induration, rupture of the skin, and formation of sinus tracts occur.

In general, eumycetoma is more circumscribed and progresses slower than actinomycetoma.

Regional lymphadenopathy is unusual; when it does occur, it is due to one of the following:

  • Lymphatic spread of mycetoma to regional nodes occurs in only 1-3% of affected patients.

  • Secondary bacterial infection or a local immunologic reaction may enlarge the regional lymph nodes.

Lymphatic obstruction and fibrosis can cause lymphedema and erythema.

Pulmonary mycetoma has been found to develop and progress more rapidly in individuals infected with HIV.

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Causes

Mycetoma occurs most often in farmers, shepherds, Bedouins, nomads, and people living in rural areas.

Frequent exposure to penetrating wounds by thorns or splinters is a risk factor, especially in combination with contaminated soil material.

Actinomycetoma can be caused by the following:

  • Nocardia species
  • Actinomadura madurae
  • Actinomadura pelletieri
  • Streptomyces somaliensis

Eumycetoma is mainly caused by P boydii (S apiospermum), Madurella mycetomatis, or M grisea. [11] Madurella has been identified in cattle dung in rural East Africa. [12]

​The color of the grains is sometimes helpful in pinpointing the exact etiologic agent. For example, the grains of M mycetomatis or M grisea ​are typically black, while those of P boydii ​and several actinomycetes are usually faint yellowish or white.

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