Alopecia and DHT

[Armando]

Alopecia and DHT


It is another crucial point in the study of baldness, although I wonder if this is widely accepted, that Dihydrotestosterone (DHT) is the one that miniaturizes the hair follicle and later causes the hair loss. This theory had much more sense around 50s when Hamilton was studying baldness and eunuchs, and it was believed that it was the man the one who produced androgens and not the woman, therefore the phenomenon of why the woman did not become bald was solved. Latter investigations pointed out than man and woman have the same hormones (androgens and estrogens).
This theory, sadly, has not been completely established, and the excellent developed drugs have not obtained the expected results. Nowadays is a theory that doesnt hold water at all, and the big laboratories have left a bit aside the investigations on this focus. A clear example is dutasteride, dual inhibitor of the 5-alpha-reductase, which controls the transformation of testosterone (T) to dihydrotestosterone (DHT), although most probably the protocol of approbation by the FDA for its medical use against baldness will not be finished.
Regardless of the paradoxical effects that T (testosterone) and DHT (dihydrotestosterone) produce on hair, depending whether it is corporal or it is on the scalp, there are big questions without solution. For instance:
1. Why one usually loses more hair when the levels of androgens are lower? With the increase of age, there are less androgens circulating.
2. Why only certain hairs on the head are affected? A genetic explanation is not suitable for me, since there are no differences in the genes of the scalp that regulate the enzyme (1).

In my opinion, it is the excess of DHT, which worsens the problem, but I think that reducing the problem of Alopecia to this unique point is not the perfect solution, particularly with the side effects that it can cause in the organism.
What do you think?
Armando

(1) Ellis JA, Stebbing M, Harrap SB. Genetic analysis of male pattern baldness and the 5alpha-reductase genes. J Invest Dermatol. 1998 Jun; 110(6): 849-53

[HairLossFight.com]

I agree with your conclusion to a degree:

In my opinion, it is the excess of DHT, which worsens the problem, but I think that reducing the problem of Alopecia to this unique point is not the perfect solution, particularly with the side effects that it can cause in the organism.

I think that if you can catch baldness early in the game and treat it vigorously and intelligently then you can mitigate the problem from getting worse. DHT's detrimental effects on hair follicles may be a trigger of other yet unknown processes that continue hair loss, such as some form of immune system activity for instance. The later treatment is started the more damage has already been done. An analogy to this idea is cancer. The sooner a cancer is identified and interventionary measures are taken to prevent its growth or spread, the greater the chances of beating it because less damage has been done. For androgenetic alopecia the complete elimination of DHT should stop hair that has not already started to miniaturize from ever doing so. As for the hair that has already started down the path of miniaturization, you may be able to stop the process from continuing, and even reverse it a little once the DHT is blocked completely, but other processes may still cause those hairs to never recover or even be lost.

There are of course other types of hair loss that are not related to the androgen DHT, such as hair loss due to thyroid dysfunction or alopecia areata for instance. But for androgenetic hair loss DHT is the primary trigger, and blocking it completely will prevent hair that has not already started to miniaturize from doing so. However, no drugs currently block ALL DHT, so depending on the sensitivity of the hair in question blocking even 90% or more of the stuff may not completely halt hair loss in some people.

Also, there are suspicions that testosterone itself (plain T) could initiative hair loss in susceptible follicles, but DHT is the most likely culprit.

You asked:

1. Why one usually loses more hair when the levels of androgens are lower? With the increase of age, there are less androgens circulating.

Older people may have less circulating androgens but their hair follicles have been exposed to androgens for a longer period of time. In the case of age-related androgenetic hair loss it is probably this prolonged exposure that is causing more loss. So what I am saying is that I think when it comes to DHT's effect on hair loss 2 factors come into play: the level of circulating DHT (more is bad) and the length of time that follicles are exposed to DHT (more is bad here too).

2. Why only certain hairs on the head are affected? A genetic explanation is not suitable for me, since there are no differences in the genes of the scalp that regulate the enzyme (1).

I'll have to read your reference in order to respond to this one fully. However, the scalp is composed of different types of cells (such as hair follicle cells and regular skin cells). Perhaps the genes that regulate the 5-alpha-reductase enzyme are not different, but perhaps the genes in the hair follicle cells do differ in some sense.

Regards,
Sam

[dawn]

my 11 year old daughter has alopecia! she is very upset and the second dr started the kenolog injection and some hair came back, but when changed drs he refuses to give the injections. What is your take on the injections?????????????????????
Thanks Dawn

[HairLossFight.com]

Hello Dawn,

I am looking into this for you by asking some doctors. A bit more information would come in handy though. First, what type of alopecia does she have? Second, why did you change doctors? I strongly recommend that you see a dermatologist, preferably one that specializes in hair and hair related conditions as soon as possible.

Sam

[HairLossFight.com]

Dawn,

Here is a post from Kevin McElwee of Keratin.com, in response to your post:

Unfortunately this is a situation that comes up all too often with AA.
You should contact the National Alopecia Areata Foundation for moral
support if nothing else http://www.naaf.org

There isn't much that can be done for chidlren - the treatments can be
worse than the condition. The new doc is probably right not to inject
kenalog, it is a very potent steroid and if used repeatedly can cause bone
thinning. In a growing child this side effect is likely to be a greater
problem and may lead to stunted growth. Most clinics that treat AA will
not treat children under 12 - and teens are usually very conservatively
treated with just topical corticosteroids which have few side effects. The
full range of treatment options is only really available to adults.

If the girl is near Vancouver she could come to the UBC Dermatology
Department where there is a special AA clinic. We have a couple of
treatments here that are rarely available elsewhere (like contact
sensitization).