All about Hair Miniaturization
Table of contents
What Is “Hair Miniaturization”?
Hair miniaturization is a hormone-driven biological phenomenon in which the hair strands become thinner, weaker, lackluster, brittle or shorter with each successive progression through the hair growth cycle, eventually leading to pattern baldness. In few cases, hair may just stop growing altogether. However, this condition can be effectively treated when diagnosed early in life, aiding the impacted individuals to experience a rejuvenated and self-esteemed life all again.
The hair follicle growth cycle comprises of 3 phases:
- Anagen (a growth phase)
- Catagen (a transitional phase)
- Telogen (a resting phase)
In genetically-susceptible hair follicles, a special form of testosterone hormone known as dihydrotestosterone (DHT) is another common cause of hair miniaturization. High levels of DHT cause the hair cycle growth phase to become progressively shorter. High levels of DHT can have a detrimental impact on the functionality and health of hair follicles by causing them to shrink progressively; eventually, DHT may even result the hair follicle to disappear.
In this way, a person’s hairs produced by these follicles becomes incapable of growing to full size because of this curtailed growth window and so they are reduced in size (diameter and length) over time until they finally disappear.
In genetically inherited hair follicles, a specific type of hair loss called “androgenetic alopecia “can cause to cease the hair cycle growth phase. The hair miniaturization caused by androgenetic alopecia typically starts as hair recedes from either or both temporal sides of the head, creating the “M” shape for which female and male pattern baldness is widely recognized. Additional miniaturization may take place at the crown (top) of the scalp, on the back crown as well, depending upon the criticality of the condition. Hair generally terminates to grow wholly as the miniaturization process continues to make hair thinner, lifeless and thus resulting to complete baldness in the affected area. According to statistics provided by NIH.gov, an estimated of 35 million American men as well as several million women is severely affected by androgenetic alopecia.
Miniaturization: The Mechanism in Genetic Balding
In DHT-susceptible miniaturization, or pattern hair loss, hair follicles undergo miniaturization, shrinking from terminal to vellus-like hairs. In any single DHT-susceptible follicular unit, the terminal hairs might be in different stages of miniaturization, and thus be of distinguished diameters. When there are plentiful of terminal hairs in a state of miniaturization, there occurs a detectable thinning of the hair or patterned baldness in the affected areas. As enough hairs in each follicular unit become miniaturized, the process may result to full baldness in that area of the scalp.
Usually, scalp hair grows in follicular units made up of 1to 4 terminal (full thickness) hairs. The process would take too long for evident miniaturization to take place secondary to shorter anagen cycles alone, specifically in aspect of the latent lag period observed in pattern hair loss that happens between the loss of a telogen hair and the appearance of an anagen hair. However, hair miniaturization reversal is clinically possible in individuals with thinning or pattern hair loss responding to finasteride treatment. It is conjectured that the miniaturization visible with pattern hair loss may be the straightforward outcome of decreasing in the cell number and, therefore, size of the dermal papilla.
In some parts of the scalp, few or all of the follicular units have the genetic vulnerability to remain secured against the adverse effects of DHT. As an outcome, these areas of the scalp might never become miniaturized, and so hair will remain to exist on these regions of the scalp for an individual’s entire life. This mainly occurs in the sides and back of the scalp, pertinently called as the “permanent zone,” while the top and front of the scalp are the primary and most likely to experience baldness and thinning.
Specifically as a result of genetic resistance to DHT in the permanent zone, a hair transplant surgery can be the most effective treatment for hair loss. In the process of hair transplant, follicular units are removed from the permanent parts of the scalp and harvested into balding regions. Due to occurrence of a phenomenon called as “donor dominance” these transplanted follicular units keep possession of their DHT-resistance even when transplanted into a region that was previously occupied by hair that were affected by genetic thinning. The follicular units, once transplanted, will proceed to grow normal, non-miniaturized terminal hairs for the entire life span of the individual. Since hairs in the permanent zone offers the donor hairs for application in surgical hair transplantation, this area of the scalp is also known as the donor area.
Miniaturization in the Donor Area
Less often, few patients encounter miniaturization in the donor area. When a patient’s donor area displays miniaturization, it minimizes the chances their chance of being a candidate for a hair transplant. Transplanting hairs that after a period of time become miniaturized and vanished invalidates the cosmetic purpose of a hair transplant procedure. Although miniaturization in the donor area is less likely to occur in men, it is the pattern in women who experience hair loss. This moderately describes why some women are candidates for surgical hair transplantation as compared to men. Only females who have a coherent donor area are recommended for hair restoration surgical procedure.
Miniaturization in the donor area is also a vital element in identifying the relevant age at which an individual is a candidate of hair restoration surgery. In most candidates with early hair loss, where severe hair loss occurs when the patient is in their late teens or early/mid-twenties, it is just next to impossible for the hair transplant expert physician to ascertain if the donor area is, in fact, going to be stable over time, or if it will ultimately miniaturize. If a consulting physician executes a hair restoration surgery on a young patient whose donor area sooner or later experiences miniaturization, then the transplant may not have the expected cosmetic effect. Not just that, but the patient will be left struggling with an additional scars and seams in the donor area from donor hair transplanting without the cosmetic advantages of restored permanent hair. That is why hair transplants are only recommended to patients of 25 years old or older.
If miniaturization in the donor area of 30-40% is indeed verified by scalp biopsy then surgery must not be the best suitable treatment option. This condition will relatively only generate temporary advantages and may lead to much more advance hair thinning. The best treatment plan recommended would be scalp biopsy. A scalp biopsy is the definitive diagnostic procedure performed prior to the best treatment plan determination.
Counter-acting the Effects of DHT
Since DHT is the major reason of male pattern baldness, why not find a way of how to stop hair miniaturization by preventing DHT for causing miniaturization? Let’s learn about what exactly happens with the medication “Propecia (finasteride)”. The finasteride obstructs the enzyme 5-alpha reductase Type II from transforming the testosterone hormone into DHT. With lower levels of DHT present in the bloodstream, lesser follicular units are revealed to the miniaturizing impacts of DHT, and thus, they continue to grow thick, healthy terminal hairs.
Rogaine, which is a topical medication for hair loss, also counter-acts the adverse impacts of DHT, but goes about it in a completely distinguished manner. DHT lowers down the growth phase of the hair cycle, resulting to progressively thinner and smaller hairs. Minoxidil, an active drug in Rogaine, works by elevating the growth phase of the hair cycle. It works well in early hair loss and usually eliminates the need of a surgical procedure. The outcome displays reverse miniaturization, lesser follicular units that encounter miniaturization.
Examples of Miniaturization
Check here for 3 examples of different intensities of miniaturization: the permanent zone with lesser to no miniaturization, medium miniaturization and immense miniaturization.
Example 1: The Permanent Zone
In the following candiadate, the transplant expert views a close-up of the side of patient’s scalp where the hair is not affected by DHT. Mostly the cluster of full thickness hairs (termed as terminal hairs), fine vellous hairs or some scattered hairs are normally seen in a donor area.
Example 2: Moderate Miniaturization
In the following condition, most of the hair is miniaturized, even though all of the hair is still present. The hairs, while still remain to present on the scalp, are so much thinner in diameter than the original hair that they give the visual look of thinning.
Example 3: Extensive Miniaturization
In this type, there is extensive miniaturization in the center of the scalp, and little loss of actual hairs. Although, because of tremendous thinning of the hair diameter, there is an impression of almost full balding in the area despite the existence of fine hair.
What these examples depicts is that, specifically in the early stages, the occurrence of balding is seemingly due to the progressive reduction in hair shaft size caused by the miniaturizing upshots of DHT, rather than the actual loss of hair.