What causes the nail to appear discolored and thickened in a fungal infection?

• A. Bacterial colonization
• B. Fungal mycelium invasion
• C. Water exposure
• D. Mineral deficiency

Answer: (B)

The appearance of discolored and thickened nails in a fungal infection is primarily caused by fungal mycelium invasion. When a fungal organism infects the nail, it penetrates the nail bed and matrix, leading to structural changes. As the mycelium, which consists of interconnected fungal filaments, grows within the nail tissues, it produces metabolic byproducts that can change the pigmentation of the nail, resulting in discoloration. Furthermore, the infection can cause an inflammatory response, leading to thickening as the body tries to fight off the fungal invasion.

This thickening is typically a response to the disruption of normal nail keratinization and structural integrity caused by the fungal presence. In contrast, other options such as bacterial colonization, water exposure, or mineral deficiency do not directly result in the specific combination of discoloration and thickened texture typically associated with a fungal infection.