DHT increases sebum by enlarging sebocyte profileration. Bacteria and yeast uses sebum as nutrition.
https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0216330
Microbiome in the hair follicle of androgenetic alopecia patients
Abstract
Androgenetic alopecia is the most common form of hair loss in males. It is a multifactorial condition involving genetic predisposition and hormonal changes. The role of microflora during hair loss remains to be understood. We therefore analyzed the microbiome of hair follicles from hair loss patients and the healthy. Hair follicles were extracted from occipital and vertex region of hair loss patients and healthy volunteers and further dissected into middle and lower compartments. The microbiome was then characterized by 16S rRNA sequencing. Distinct microbial population were found in the middle and lower compartment of hair follicles. Middle hair compartment was predominated by Burkholderia spp. and less diverse; while higher bacterial diversity was observed in the lower hair portion. Occipital and vertex hair follicles did not show significant differences. In hair loss patients, miniaturized vertex hair houses elevated Propionibacterium acnes in the middle and lower compartments while non-miniaturized hair of other regions were comparable to the healthy. Increased abundance of P. acnes in miniaturized hair follicles could be associated to elevated immune response gene expression in the hair follicle.
https://en.wikipedia.org/wiki/Cutibacterium_acnes
=the immune response in the balding scalp is a reaction to an increased quantity of pain-causing bacteria and itch-causing yeast, feeding off the increased sebum
https://link.springer.com/article/10.1007/s11046-019-00345-8
Investigation on Microecology of Hair Root Fungi in Androgenetic Alopecia Patients
Abstract
Background
This study focused on the differences in hairy root fungal microecology between androgenetic alopecia patients and healthy individuals.
Methods
Light microscopy was used to observe the morphology of hairy roots. Morphological observations were also performed in the positive specimens using scanning electron microscopy and transmission electron microscopy. The high-throughput sequencing method was used to detect the fungal microecology of hairy roots at different sites. Moreover, the comparison of fungal loads of
Malassezia in different group and scalp area were tested by PCR.
Results
The fungi in the hair root observed by optical microscopy are mainly
Malassezia yeast.
The positive rate of Malassezia in the hair loss group (60%) was higher than that in the control group (40%). The detection efficiency of
Malassezia examined by scanning electron microscopy was higher than that by light microscopy. Results acquired from high-throughput molecular sequencing of fungi suggested that
Ascomycota was the dominant species, whereas in the occipital hair roots of the control group
Basidiomycota was the dominant species in the hair loss group. Malassezia followed by Trichosporon were the most abundant fungal genera. The changes in abundance at the top and occipital region of the control group were more significant than those of the genus
Fusarium, followed by
Epicoccum and
Malassezia.
The load of Malassezia located on calvaria in the alopecia group was significantly higher than that in the control group. In the alopecia group, the load of Malassezia on the scalp was higher than that on the occipital region. The load of
Malassezia globosa and
Malassezia restricta in the hair loss group was higher on calvaria and occipital areas.
Conclusion
Malassezia had a positive correlation with the incidence of androgenic alopecia.
https://en.wikipedia.org/wiki/Malassezia
Role in human diseases[edit]
Identification of
Malassezia on skin has been aided by the application of molecular or DNA-based techniques.
These investigations show that the Malassezia species causing most skin disease in humans, including the most common cause of dandruff and seborrhoeic dermatitis, is M. globosa (though M. restricta is also involved).[8] The skin rash of
tinea versicolor (
pityriasis versicolor) is also due to infection by this fungus.
As the fungus requires fat to grow,[4] it is most common in areas with many sebaceous glands: on the scalp,[16] face, and upper part of the body. When the fungus grows too rapidly, the natural renewal of cells is disturbed, and dandruff appears with itching (a similar process may also occur with other fungi or bacteria).
A project in 2007 has sequenced the genome of dandruff-causing
Malassezia globosa and found it to have 4,285 genes.
[17] M. globosa uses eight different types of
lipase, along with three
phospholipases, to break down the oils on the scalp. Any of these 11 proteins would be a suitable target for dandruff medications.
M. globosa has been predicted to have the ability to reproduce sexually,
[18] but this has not been observed.
So:
Antimicrobial effects of tea-tree oil and its major components on Staphylococcus aureus, Staph. epidermidis and Propionibacterium acnes.
Raman A1, Weir U, Bloomfield SF.
Author information
Abstract
Major components of two tea-tree oil samples were identified using thin layer and gas-liquid chromatography (TLC and GLC). Using a TLC-bioautographic technique, the tea-tree oils, terpinen-4-ol, alpha-terpineol and alpha-pinene were found to be active against Staphylococcus aureus, Staph. epidermidis and Propionibacterium acnes whereas cineole was inactive against these organisms. The MIC values of the three active compounds increased in the order alpha-terpineol < terpinen-4-ol < alpha-pinene for all three micro-organisms. MIC values of the tea-tree oils and terpinen-4-ol were lower for P. acnes than for the two staphylococci. This study supports the use of tea-tree oil in the treatment of acne, and demonstrates that terpinen-4-ol is not the sole active constituent of the oil.
In Vitro Activities of Ketoconazole, Econazole, Miconazole, and Melaleuca alternifolia (Tea Tree) Oil against Malassezia Species
The MICs shown in Table 1 demonstrate that ketoconazole was the most active of the imidazoles, followed by miconazole and econazole, which were similar in activity. M. furfur was the species least susceptible to imidazoles: the remaining species were similar. Tea tree oil was active against allMalassezia species, for which the MICs were similar.
Tea tree oil and products containing the oil have been evaluated in vivo for the treatment of superficial fungal infections such as onychomycosis and oral candidiasis, with some favorable clinical outcomes (1, 9). Reports have been published previously describing the in vitro susceptibility of Malassezia species to tea tree oil (6, 17), and the present study confirms and extends these findings. However, there are no reports on the use of tea tree oil specifically for the treatment of Malassezia skin infections. Most tea tree oil products contain 5 to 10% tea tree oil, and this is likely to be adequate for clinical use. Different commercially available 100% tea tree oils vary little in their antimicrobial activity (2), however, the activity of tea tree oil can be antagonized by various excipients used in the formulation of products (7). In addition, as with many topical agents, there is a low risk of allergic reactions to 100% tea tree oil. We have recently shown the prevalence of such allergy to be approximately 5% (Greig et al., unpublished data).
In conclusion, this work has shown that individualMalassezia species vary in their susceptibility to several antifungal agents, with M. furfur being the least susceptible of the species tested. Tea tree oil may be a suitable alternative topical agent. In view of the apparent emergence ofMalassezia as opportunistic pathogens, these data may have clinical significance.
= Tea tree oil kills both acne-causing bacteria and dandruff-causing yeast
