new thread
From a Procter and Gamble press release:
P&G Scientists Pinpoint Cause of Dandruff; Malassezia furfur (M. furfur) Excluded as Primary Suspect
PARIS, July 1 /PRNewswire-FirstCall/ -- Data presented today by The
Procter & Gamble Company (NYSE: PG) research scientists at the 20th World
Congress of Dermatology (WCD) suggests that dandruff does not result from an
overabundance of Malassezia furfur (M. furfur) fungus as previously thought.
Rather, common dandruff, the scalp condition affecting more than 50 percent of
Caucasians and 80 percent of people of African descent, is caused by the lipid
waste of two other Malassezia species, M. restricta and M. globosa.
In a research study conducted by Thomas Dawson, Jr., Ph.D., senior
scientist in beauty care technology for P&G, titled, "Fast, Non-invasive
Method for Molecular Detection and Speciation of Malassezia on Human Skin, and
Application to Dandruff Microbiology," scalp samples from 70 people with
dandruff showed the presence of Malassezia species. But in these cases,
M. restricta was present in 70 percent and M. globosa in 45 percent.
M. furfur was not detected in any of the samples.
Malassezia is a lipophilic fungal genus, members of which are part of the
normal human scalp flora. M. restricta and M. globosa feed on lipids secreted
from the hair follicles. The partially digested lipids that linger on the
skin cause the familiar irritation of the scalp that leads to dandruff.
"We have been studying dandruff and other scalp conditions for many years,
concentrating on the specific organism that causes the disorder," said
Dr. Dawson. "We expect these data will provide insight into the development
of new approaches to dandruff treatment."
"These new data on the real cause of dandruff are a major step forward in
understanding dandruff that will be important to the dermatology community,"
said Boni E. Elewski, MD, Professor of Dermatology at the University of
Alabama, Birmingham, and internationally-recognized authority on cutaneous
fungal infections and dandruff. "This research will allow development of more
effective anti-dandruff treatments that will not only treat the condition, but
may also help prevent it from occurring."
Dr. Dawson's findings also apply to seborrheic dermatitis, a severe form
of dandruff that affects up to 10 percent of Caucasians and leads to heavy
flaking, severe itchiness, redness and inflammation. Earlier work by this
team of P&G scientists has shown that excess lipids are correlated to dandruff
and seborrheic dermatitis, and this study showed that reducing the amount of
sebum by more frequent washing improved the clinical signs of seborrheic
dermatitis. This also lends support to the theory that sebum has a positive
effect on the growth of fungus.
Additional Research
Dr. Dawson noted that P&G will conduct detailed quantitative studies to
better define the role of other Malassezia fungi, as well as the role of
individual sensitivity to M. globosa and M. restricta.
"P&G is committed to researching and understanding the science behind skin
conditions like dandruff, so we can continue to provide medical professionals
and consumers with the most effective treatments," said Eric Armstrong,
Vice President of Research & Development for the company's Global Hair Care
Division. "In particular, P&G will seek to understand, identify, and
characterize the role of individual lipids associated with dandruff and
seborrheic dermatitis, in order to continue to develop the highest efficacy
anti-dandruff products. In addition, P&G scientists will explore the reasons
why some patients react to the presence of Malassezia, while others do not."
Malassezia and Dandruff
In years past, the scientific community disagreed about the role of
Malassezia in dandruff. Some scientists argued that an increase in cell
turnover on the scalp was the main cause of dandruff, and microorganisms, such
as Malassezia, only reflected the underlying abnormality of the skin.
In the 1970s and 80s, with scientific studies demonstrating the
effectiveness of specific anti-fungal agents in improving chronic scalp
conditions, scientists proved a correlation between Malassezia in both
dandruff and seborrheic dermatitis. Scientists assumed that M. furfur was the
cause.
Only recently have scientific studies supported the relationship between
Malassezia and lipids in connection with dandruff. Past studies show
Malassezia's involvement in a number of pathologies related to alterations of
the skin's surface lipids. Results from this study suggest that only two of
nine Malassezia species are present on the scalp that could digest the
naturally occurring lipids. In addition to showing the connection between
dandruff and M. restricta and M. globosa, this research also shows that to
remain viable, Malassezia uses its enzymes to break down non-irritating
triglycerides (lipids) into irritating free fatty acids.