The primary fungal agents known to attack human hair are dermatophytes, Malassezia species, and the fungi that cause piedra. These organisms lead to various hair-related infections, collectively known as trichomycoses.
Understanding Hair Fungal Infections (Trichomycoses)
Hair infection by fungal agents, medically termed trichomycoses, is a common dermatological concern affecting individuals worldwide. These infections can range from superficial issues like flaking to more severe conditions impacting hair structure and scalp health.
Key Fungi Responsible for Hair Infections
While numerous fungal species exist, certain types are particularly notorious for their ability to colonize and damage hair shafts. The most common culprits include:
- Dermatophytes:
These are a group of fungi that specialize in breaking down and consuming keratin, the protein that makes up hair, skin, and nails. They are the primary cause of tinea infections, often referred to as "ringworm," even though no worm is involved. When dermatophytes infect the scalp and hair, it's known as tinea capitis. This can lead to brittle hair, hair loss, and scaly patches. Common genera include Trichophyton and Microsporum. - Malassezia Species:
Malassezia are a genus of yeasts that are naturally found on the skin surfaces of many warm-blooded animals, including humans. Under certain conditions, such as increased humidity, oily skin, or a compromised immune system, these yeasts can overgrow. While often associated with skin conditions like dandruff (pityriasis capitis) and seborrheic dermatitis, they can also affect hair follicles, contributing to folliculitis and other hair-related issues. - Fungi Causing Piedra:
Piedra refers to a fungal infection of the hair shaft characterized by the formation of hard nodules or concretions along the hair. There are two main types:- Black Piedra: Caused by Piedraia hortae, this infection results in dark, gritty nodules on the hair shaft, typically in warm, humid climates.
- White Piedra: Caused by species of Trichosporon, this infection produces softer, lighter-colored nodules that can be easily dislodged from the hair. Both forms can make hair brittle and prone to breakage.
How Fungi Attack Hair
These fungi attack hair by utilizing enzymes to break down keratin, leading to weakened hair shafts, inflammation of the surrounding scalp, and often visible signs like scaling, redness, or hair breakage. The specific method and location of attack (e.g., inside or outside the hair shaft) vary depending on the fungal species and the type of infection.
