Which of the following is false about mycetoma ?
**Core Concept**
Mycetoma is a chronic granulomatous infection of the skin and subcutaneous tissue caused by filamentous bacteria (actinomycetoma) or fungi (eumycetoma). It is characterized by the formation of grains or granules in the infected tissue.
**Why the Correct Answer is Right**
Mycetoma is typically caused by organisms such as *Nocardia*, *Streptomyces*, or *Madurella mycetomatis*. The infection usually enters the body through a skin wound or trauma. The organisms produce granules or grains that become lodged in the tissue, leading to a chronic inflammatory response and granuloma formation. **The grains are typically sterile and can be used for laboratory diagnosis**.
**Why Each Wrong Option is Incorrect**
**Option A:** Mycetoma is a rare disease. This is true, as mycetoma is a relatively rare condition, especially in comparison to other skin infections.
**Option B:** Mycetoma is caused by a single type of organism. This is false, as mycetoma can be caused by a variety of filamentous bacteria or fungi.
**Option C:** The grains in mycetoma are always infected with the causative organism. This is false, as the grains are typically sterile and can be used for laboratory diagnosis.
**Clinical Pearl / High-Yield Fact**
Mycetoma is often misdiagnosed as other skin infections, such as tuberculosis or leprosy. A key diagnostic clue is the presence of grains or granules in the infected tissue.
**Correct Answer: B. Mycetoma is caused by a single type of organism.**