Stages of Hair Loss

It is a common knowledge that baldness occurs in degrees and is a gradual phenomenon. Since it is not possible to convey the extent of baldness in words, a classification system was developed by Dr. Norwood. This is the most commonly used sytem today, although other more complicated systems are also available.

Broadly speaking, Norwood classification attempts to divide baldness in seven stages with stage I  being normal adult hairline and stage VII being total possible baldness. Although, there are many flaws in this system, it still gives a basic idea regarding the extent of baldness in an individual.

Stage I

Essentially normal adult male hairline (not to be confused with 'juvenile hairline'). Temporal recessions are well defined   with frontal hairline in normal position. No miniaturisation in crown region.

Stage II

The frontal hairline shows slight recession(< 2 cm), with more pronounced recession in temporal area.
The "A" variant implies that hair line is receding uniformly and that frontal forelock is not spared. This means
exaggerated appearance of baldness and larger requirement of hair during transplant.

In this stage hair transplant should be done if the baldness is stable. Usually a single session is adequate.

Many surgeons defer operating in such patients, especially if they are young.

Stage III

This stage can be considered as watershed for transplant, because now the baldness is very obvious
and most transplant surgeons would consider performing a procedure in such patients. There is definite recession
in frontal hairline combined with deep temporal areas and usually thinned out look in most of frontal area.
Crown may also show miniaturisation and/or actual hair loss (Stage III Vertex)

State IV

This is a more advanced state of baldness, in which frontal and frontotemporal recession is deeper than in State III
and the density of hair in these areas is noticeably reduced. As the baldness moves from front to back,
and circumferentially in crown area; a bridge of healthy hair remains in the mid section of scalp.
This area called the 'bridge' is characteristic of stage IV.  Loss of bridge, is seen is considered a feature of
advanced baldness.

Stage V

Area of baldness keeps increasing and thinning of bridge segment is present.

Stage VI

In this stage there is total disappearance of the bridge segment that separates the two main areas of baldness.
The depth of the frontal and crown areas has expanded sideward and backwards.
In some individuals, frontal forelock may be spared to become 'isolated forelock'.

Stage VII

This is the most advanced stage of hair loss. In this stage only the universal safe zone remains.
Hair transplant is useful only in those individuals of stage VII who have good hair characteristics.

Hair transplant is possible from stage II through VII. Advanced stages of baldness usually require more than
one session to achieve maximum benefit.
In selected individuals mega sessions can be planned to cover large areas in one go.

Hair Fall and Stem Cells

There was a very interesting news item in field of hair transplant which I would like to share. This concerns cause of male pattern alopecia.
It is a known fact that in male pattern balding (Androgenetic alopecia), hair follicles don't disappear. They become so small by a process called “miniaturization” that they are not visible to naked eye. Although, we know that DHT is responsible for this process, how exactly it causes miniaturization of hair roots is still not known.

One theory of miniaturization says that DHT causes stem cell depletion in hair follicles of bald areas. A new study, published in the Journal of Clinical Investigation, tries to shed some light on this.  The research team led by Dr. Costarelis, MD collected cell samples from bald and non bald areas from the same persons and counted the number of stem cells present. They were surprised to find that bald areas had the same number of stem cells as hair bearing areas. When they looked further, they found that another cell type, which develops from stem cell, called progenitor cell was deficient in miniaturized follicle.

Dr Costarelis says that, "This implies that there is a problem in the activation of stem cells converting to progenitor cells in bald scalp." As of now, why or what causes the arrest in progression of stem cells to progenitor cells is not known. "However, the fact that there are normal numbers of stem cells in bald scalp gives us hope for reactivating those stem cells," notes Costarelis.
The logical next step would be to identify the factors that arrest this progression and to remove them. A locally applied agent or growth factors that can help stem cells to get converted to progenitor cells would also be very useful.
I have used growth factors injections in some of my patients. The results, especially when used with PRP are good but temporary. The repeated injections overcome the cost benefit. The big break will be an agent that can grow hair permanently. Till then we have hair transplants.