P8.91 NEW HYPOTHESIS ABOUT COMMON BALDNESS

AJ Soler

Elda- Alicante, Spain

Common baldness or alopecia affects a high number of people. The etiology and pattern of hair loss has not been completely explained, probably because hair is one of the most dynamic mammalian structures. The hair follicle (HF) can both renew itself through an intrinsic stem cell population and has the ability to cycle asynchronously.

Sebum is vital for hair growth, and it is created and eliminated continuously due to its high instability. In this hypothesis, the existence of a sebum flow outward and another one inward the HF is supposed. If there are problems of elimination in its way outward, this causes problems in the inward flow. Therefore the detention of sebum flow towards the inside of the HF is proposed as the initial and triggering factor of common baldness.

This hypothesis provides a simple explanation of the characteristic pattern of hair loss and why alopecic areas do not appear at the sides and back of head. These are the areas we rest daily on absorbent surfaces such as the pillow, where sebum can be drained directly, avoiding in this way its possible detention. The hair located in the “sensitive” areas has to eliminate sebum by carrying it longitudinally along the hair shaft or in a transversal way by contact with neighbouring hair.

On the other hand, it seems that the follicular papilla (FP) is a result of migration of transient amplifying cells from the bulge region to the hair germ during anagen induction. It is then logical to think that the route of such cells is the same that sebum must cover. If sebum stops, then its physical, chemical and biological properties change and may cause an alteration or decrease of the cells that reach their aim, which can explain the miniaturization process that is observed in common baldness. From that point the rest of alterations in other involved systems, such as the hormonal, immune, circulatory, fibrosis processes, etc… can be explained.

Baldness is a degenerative process that affects each hair individually, easily reversible at the initial stages and more difficult to reverse as time goes by.