Trichosporonosis (also referred to as Piedra) is a type of hair disorder that is caused by a fungus.
There are two distinct types:
- White Piedra
- Black Piedra
White Piedra or Tinea blanca is a fungal infection in the hair shaft which is caused by different species of fungi in the genus Trichosporon. It is distinguished by soft nodules comprising of yeast cells and arthroconidia that surround hair shafts. Black Piedra is a form of fungal infection caused due to Piedraia hortae. Black Piedra is more commonly seen in the tropical regions of the world having high temperatures and humidity such as South American countries including Brazil and Southeast Asia. Whereas, White Piedra is more common in temperate and semitropical climates such as that in South America, Europe, Japan, Asia and parts of southern United States.
In addition, the black piedra and white piedra affect the hair in different body locations. Black piedra usually affects scalp hair, whereas white piedra more commonly affects pubic hair, axillary hair, beards, mustaches, and eyebrows and/or eyelashes. However, in Brazil, white piedra is seen to have affected scalp hair most commonly. White piedra affects horses and monkeys, in addition to humans. Black piedra occurs in monkeys and humans.
The two most important causal factors responsible for giving rise to Piedra are, the environment and typical skin flora. In case of Black Piedra, the source of infection appears to be in the soil; nevertheless infection also has been traced to organisms in the crops and stagnant water. Whereas, in case of White Piedra, the source of infection may be present in the soil, air, water, vegetable matter, or sputum or on body surfaces; the mode of transmission being unclear in humans.
Signs & symptoms:
Findings in White Piedra:
- White Piedra comprises of loosely attached nodules or gelatinous sheaths which are lightly pigmented and have a soft texture.
- The areas that are most commonly affected are moustaches, beards, pubic and axillary hair, and eyebrows and eyelashes. When it is extensive, it may appear on the scalp.
Findings in Black Piedra:
- In Black Piedra, the nodules are firmly attached and hard in consistency which vary in size to as large as a few millimeters in diameter.
- The area that is most likely to be affected is the scalp hair.
- The fungus grows into the hair shaft; eventually it may lead to breaking the hair as a result of structural instability.
- Tinea capitis
- Trichorrhexis nodosa
- Shaving or cutting the hair is the treatment of choice.
- Oral Terbinafine is used for treating Black Piedra.
- Topical antifungals may be used in the treatment of White Piedra.
The most common side-effect being the loss of the structural integrity of the hair shaft, which results into breakage.
The prognosis is good after treatment. Recurrence is rare. Removal of the affected hair is generally curative. If not treated, spontaneous remissions may occur.