Assessing the Extent of Baldness
Anticipating Short and Long-Term Hair Loss

The cardinal rule for the proper planning of every hair transplant is to always anticipate the patient's worst case scenario. Although any hair loss is never really "predictable, " one must still make an educated judgment as to what the future hair loss will most likely be so that rational short and long-term plans can be formulated.

In anticipating the patient's long-term hair loss, we find three factors to be useful. Since the inheritance of male pattern baldness appears to be polygenic 9 , it is impossible to make accurate judgments from the family history. In our own experience, we find that if a specific pattern of hair loss is recognizable in another family member that matches the patient's own hair loss pattern and chronology, this can be useful in judging how rapidly the hair loss may progress and what the final pattern might be.

The second factor, the personal history may be of value once the patient has reached his late 20's. When taking a history, it is important to ascertain not only when the hair loss began, but the present rate of loss. Even for the patient in his late 20's, it is very hard to predict the future course when the present hair loss is in its early stages. The most difficult of all hair loss patterns to interpret is the Norwood Class III, as this patient has not yet "tipped his hat" as to the direction of future loss.

The third means of evaluating hair loss is to measure the degree of miniaturization in both the donor and recipient areas. Miniaturization is the progressive diminution of hair shaft size reflected in both the diameter and length, due to the genetically determined effects of aging and/or androgenic hormones on the terminal hair follicle. We find that miniaturized hairs normally represent no more than 20% of the terminal hair population. Because miniaturization is a relative measurement (comparing finer hair to the thickest hair), it takes substantial experience before this measurement can be useful to the individual clinician. In our experience, from examining and following, over 5, 000 patients with the Hair Densitometer 10 , we have found that assessing the degree of miniaturization has useful predictive value when evaluating the risks of hair loss and in establishing hair loss patterns. A high degree of miniaturization in the upper portion of the donor area suggests that the donor fringe will contract over time. A high degree of miniaturization throughout the donor area indicates that all of the patient's hair is unstable and that he is at risk to have diffuse unpatterned alopecia and of becoming extensively bald (see section on Diffuse Androgenetic Alopecia ).

Miniaturization in the recipient area can often delineate which areas of the scalp are most likely to bald and which are stable, anticipating the patient's future Norwood classification. In the very early stages of hair loss, increased miniaturization can anticipate future balding even before any loss is clinically apparent. Usually large numbers of hairs undergo miniaturization before any are actually lost. Therefore, even with clinically significantly thinning, the actual total number of hairs present in the balding area may be the same as the patient's original hair counts. The percentage of terminal hairs, however, would be markedly diminished. For the most reliable prediction of the final hair loss pattern, the patient should be over the age of 30 and have had significant hair loss already, although this measurement is, of course, useful at any age.

As mentioned above, predicting future hair loss in the Class III patient is especially problematic. In contrast to the Class III Vertex patient, who we may reasonably expect will evolve into a Class V or VI (especially if there are Class V or VI family members), it is impossible to accurately predict if the Class III patient will stabilize and remain at this class or will become more extensively bald. However, a significant degree of miniaturization (>20%) measured in a young person across the top and crown, but sparing the bridge, would suggest the likely possibility of future progression to at least a Class IV or V (and possibly to a Norwood Class VI or VII pattern). Widespread areas of increased miniaturization throughout the front and top of the scalp indicate the development of either diffuse, patterned or unpatterned alopecia (see section on Diffuse Androgenetic Alopecia ).

We feel that in predicting the short-term loss, the extent of miniaturization in the recipient area, as well as the rapidity of the loss, are important. In rapid hair loss, the degree of miniaturization in the balding area is well over 50%, and this can be easily determined with the densitometer. Often the reason a person seeks a consultation for hair loss is that there is some change in the "rate" of his hair loss. A patient who is gradually losing his hair is less likely to seek help than a patient who suddenly has an acceleration in the rate that he is losing hair. However, it is the very patient who is first seen while entering an accelerated stage of hair loss that is at greatest risk for being unhappy with the outcome of his surgery. Careful counseling to give him a clear understanding of the natural progression of his balding is critical in achieving realistic patient expectations. In treating patients with rapid hair loss (and adequate donor reserves), goals must be conservative and clearly defined before any surgery is attempted.

A history of diffuse, rapid hair loss, especially in a young patient, can be an ominous sign and may reflect an evolving Norwood VII pattern. This is often associated with a high degree of donor miniaturization, significant bitemporal recession, and the absence of the elevated triangular segment of hair in the parietal region that would define a Norwood Class VI. (The superior portion of the rim of Class VII patient, when viewed from the side, is flat, or slopes gently backwards. This is in contrast to the Class VI patient who, when viewed from the side, has an elevation, that has its peak just anterior to the ear and is the residual of the Class V bridge that separated the anterior and posterior portions of the scalp.) Occasionally, a young patient is seen with a complaint of loss of hair volume, but that clinically appears to be normal. If densitometry reveals a donor density in the range of 1.0 to 1.5 hairs/mm 2 , with miniaturization in this area of 35% or greater, this patient has a high risk of being extensively bald with insufficient donor hair and, in our opinion, should generally not be transplanted.