Mycetoma

Overview

Mycetoma is a slow, long-lasting infection that affects the skin and the tissues beneath it, and over time can involve muscle and bone. It usually develops on the foot, which is why it is often called Madura foot, but it can occur on the hands or other body parts exposed to soil. The infection causes swelling, firm lumps, and channels in the skin called sinuses that drain fluid containing tiny grains.

There are two main types depending on the cause. When fungi are responsible it is called eumycetoma, and when bacteria are responsible it is called actinomycetoma. The two types look similar but need different treatments. Mycetoma is most common in tropical and subtropical regions and tends to affect people who work outdoors. It progresses slowly but can cause serious damage if left untreated.

Symptoms

Mycetoma develops slowly, often over months to years, and is usually painless in the early stages. Typical features include:

• Painless swelling of the affected area, most often the foot.
• Firm lumps or nodules under the skin.
• Draining sinuses: Small channels that open onto the skin and discharge fluid or pus.
• Grains in the discharge: Tiny colored particles, which may be black, white, yellow, or red depending on the organism.
• Gradual spread and deformity as deeper tissues and bone become involved.
• Pain if a secondary bacterial infection develops or if bone is affected.

Causes

Mycetoma is caused by certain fungi or bacteria that normally live in soil and on plants. The organisms enter the body through a small cut, thorn prick, or other wound, often on the foot of someone who walks barefoot or works with soil.

• Eumycetoma: Caused by fungi.
• Actinomycetoma: Caused by certain bacteria.

Once inside, the organisms slowly multiply and form the characteristic grains. Mycetoma is not spread from person to person, and it relates to environmental exposure rather than contact with an infected individual.

Risk Factors

• Living or working in tropical or subtropical regions where mycetoma occurs
• Outdoor work involving soil, such as farming or herding
• Walking barefoot, which exposes the feet to cuts and soil organisms
• Repeated minor skin injuries from thorns or splinters
• Being a young to middle-aged adult, the group most often affected

Diagnosis

Diagnosis is based on the appearance, the grains in the discharge, and tests to identify the organism and how deep the infection goes.

• Examination of the grains: Studying the color and structure of grains from the sinuses under a microscope.
• Culture and molecular tests: To identify whether a fungus or bacterium is responsible and which specific organism it is.
• Biopsy: A tissue sample to confirm the diagnosis.
• Imaging: Ultrasound, X-ray, or MRI to see how far the infection has spread, including to bone.

Telling the two types apart is essential because treatment differs.

Treatment

Treatment depends on whether the cause is fungal or bacterial and how advanced the infection is.

• Actinomycetoma (bacterial): Often responds to a long course of antibiotics, sometimes a combination, and many cases can be cured with medication.
• Eumycetoma (fungal): Treated with long-term antifungal medication, frequently combined with surgery to remove infected tissue, and it tends to be harder to cure.
• Surgery: May be needed to remove masses or, in severe advanced cases, more extensive procedures.
• Wound care: And treatment of any added bacterial infection.

Treatment is usually prolonged, and follow-up is important because the infection can return.

Prevention

There is no vaccine, so prevention focuses on protecting the skin from injury and soil organisms:

• Wear shoes and protective footwear, especially when working outdoors
• Clean and cover cuts, scratches, and thorn pricks promptly
• Use gloves and protective clothing when handling soil
• Seek care early for unexplained, slowly growing swelling or lumps

When to See a Doctor

See a doctor if you have a slowly growing, painless swelling or lumps, particularly on the foot, or sinuses that drain fluid with tiny grains, especially if you live in or have visited a region where mycetoma occurs. Seek prompt care if you develop:

• Increasing pain, redness, warmth, or fever suggesting added bacterial infection
• Rapidly spreading swelling
• Signs that the infection is affecting deeper tissues or bone, such as difficulty using the limb

Related Topics

Frequently Asked Questions

References

1. World Health Organization (WHO). Mycetoma.
2. Centers for Disease Control and Prevention (CDC). Mycetoma.
3. MedlinePlus, U.S. National Library of Medicine.
4. StatPearls, National Library of Medicine. Mycetoma.