Which of the following is commonly known as a type of skin fungus?

Ringworm is a term used to describe a common type of skin fungal infection, technically known as dermatophytosis. This condition is caused by a group of fungi that thrive on the keratin found in skin, hair, and nails. Ringworm can affect various animals and humans, leading to circular, itchy red patches on the skin that may have raised borders. It's particularly common in pets like cats and dogs, as well as in humans, making it a significant concern in veterinary and medical practices.

In contrast, candidiasis is caused by the yeast Candida and primarily affects mucosal tissues, not skin in the same manner as ringworm. Histoplasmosis is a respiratory illness caused by the fungus Histoplasma capsulatum, which primarily affects the lungs and is not a skin fungus. Aspergillosis, caused by the Aspergillus species, can affect various body systems, predominantly the respiratory system, and is also not classified as a skin fungus like ringworm. Each of these other options involves different types of fungi with distinct characteristics and potential impacts on health, illustrating why ringworm is the fitting choice for a common skin fungus.