Introduction to Medical Mycology I & II

Fungi are eukaryotic organisms with true nuclei and a nuclear membrane.

The cell wall of fungi is composed of chitin, a polymer of N-acetylglucosamine (NAG) sugar. This structure is unique to fungi.

Fungal cell membranes contain ergosterol, a sterol that is not present in human cells. This difference is crucial for antifungal drug development.

Filamentous fungi are characterized by branching filaments called hyphae. These hyphae can be either septated (divided by cross walls) or non-septated (continuous).

A mass of hyphae is called a mycelium. This dense network of interwoven filaments is responsible for the fungus's growth and spread.

Unicellular fungi, typically rounded or oval in shape, are classified as yeasts. They reproduce by budding.

Some fungi can exist in both yeast and mold forms, depending on environmental conditions. This is known as dimorphism.

Fungal infections in humans are collectively referred to as mycosis. Different types of fungal infections exist, depending on the location and severity.

Superficial mycosis involves the outermost layers of the skin, causing symptoms like hypo or hyperpigmentation. A common example is Pityriasis versicolor, caused by Malassezia spp.

Cutaneous mycosis affects deeper layers of the skin, hair, and nails. One well-known example is Dermatophytosis, or Tinea, caused by keratinophilic filamentous fungi called Dermatophytes.

Fungal infections that affect the skin, hair, and nails, caused by dermatophytes like Trichophyton, Microsporum, and Epidermophyton. They are spread through direct contact with infected individuals, animals, or soil, or indirectly through shared personal items like clothing, combs, and towels.

A type of dermatophytosis affecting the scalp and hair, often causing hair loss and scaling.

A type of dermatophytosis affecting the beard area, often causing inflammation, itching, and hair loss.

A type of dermatophytosis affecting the smooth, non-hairy skin of the body, often causing ring-shaped lesions.

A type of dermatophytosis affecting the feet, particularly the toe webs and soles, commonly known as "athlete's foot."

A type of dermatophytosis affecting the groin area, often causing itchy red patches.

A type of dermatophytosis affecting the nails, also known as "onychomycosis." It causes thickening, discoloration, and sometimes crumbling of the nails.

Fungal infections that involve the subcutaneous tissue, muscle, and fascia, typically caused by fungi like Madurella and Acremonium.

Fungal infections that involve multiple organ systems, commonly caused by airborne fungi like Aspergillus, Cryptococcus, and Histoplasma.

Fungal infections that occur in individuals with weakened immune systems, often caused by common environmental fungi like Candida and Aspergillus.