Androgenetic alopecia (male pattern baldness) is by far the most common cause of hair loss in approximately 50% of men suffering from hair loss diseases. Although it is a medically benign condition, it affects the psychology of the patient to a large extent. The aim of this article is to describe the various hair loss restoration treatment options available for male pattern hair loss (MPHL).
Pathophysiology of hair loss
Let’s understand the different factors underlying androgenetic alopecia. As its name implies, androgenetic alopecia involves both genetic and hormonal factors. As already discussed, the male hormone androgen plays a major physiological role in the disease, but it is the Genetics which makes individual pre-disposed to the disease by determining both the density and the location of androgen-sensitive hair follicles on specific sites of the scalp.
The influence of hormonal factors starts becoming evident at the puberty when genetically programmed hair follicles come under the influence of male hormones. The interaction of these two factors result in shortening of the anagen phase and a miniaturization of the hair follicles that both leads to thinning of hair fiber and its falling.
Hair Loss patterns in Androgenetic alopecia
As men progress through their twenties, slight frontal-temporal recessions start becoming evident. The hair line has a concave appearance on each side and a lower peak in the middle. This stage is known as the Norwood Hamilton stage II. Developed by Dr. O’Tar Norwood, this scale is a very useful scale for identifying degree of hair loss and is understood by most of hair loss restoration doctors.
Norwood III is considered the first evidence of balding in androgenetic alopecia (male pattern baldness) and the most advanced balding is known as a class VII. Then there are Type “A” variants in which the forelock in the middle tends to recede along with the frontotemporal areas, and in which there is be less overt crown loss than in the regular III, IV, and V patterns.
Inheritance Pattern of the Disease
The exact inheritance pattern of androgenetic alopecia is still debated. But it is mostly considered to be autosomal dominant and polygenic which can be inherited from either parent.
It is interesting to note that androgen levels of male with androgenetic alopecia have been found to be perfectly normal. It is the intracellular androgen metabolism, which is the major determining factor. The metabolism of androgen inside our body involves 2 steroid-metabolizing enzymes (5α-reductase and aromatase), and androgen receptor proteins (ARPs). Altered levels of these components are believed to responsible for the difference in severity of the disease between men and women and also for different patterns observed.
5α-reductase isoenzymes, type I and II, are both part of the normal androgen metabolism and their function is to reduce testosterone to dihydrotestosterone (DHT). The 5α type I isoenzyme is located mainly in sebaceous glands, epidermal and follicular keratinocytes, dermal papilla cells, and sweat glands. The 5 α reductase type II isoenzyme is located mainly in the root sheaths of the scalp hair follicle.
Both type I and type II isoenzymes most likely play an important role in androgenetic alopecia since they have been found in increased levels in frontal follicles compared to occipital follicles where balding is most commonly seen. Women have about 3 to 3.5 times less 5α-reductase (types I and II) in their follicles as compared to men. The role of these isoenzymes play in androgenetic alopecia is confirmed by the fact that men with a genetic deficiency of 5α-reductase type II isoenzyme have never been found to develop androgenetic alopecia.
ARPs are the other class of metabolites present in androgen sensitive areas. These ARPs are also found in the outer root sheath and dermal papilla fibroblasts of scalp hair follicles. Since the levels of these ARPs are found to be 30% greater in the balding frontal hair follicles than in non-balding occipital follicles of both men and women, these are thought to play some role in the disease, but the mechanism of their action is not very clear yet.
Hair Loss Restoration Treatment
Many scientific studies for hair loss restoration have been conducted for the individuals suffering from androgenetic alopecia. And most of these studies have confirmed that considerable re-growth is possible following treatment with finasteride, minoxidil, spironolactone or estrogen even at very advanced stages of the condition.
Of the above mentioned treatments, Topical minoxidil (Rogaine) and Oral finasteride (Propecia) are the only Medical Hair Restoration Treatments that have been approved by the US Food and Drug Administration (FDA) for MPHL. Their use as medical hair restoration is indicated in all the cases of mild to moderate MPHL in men older than 18 years.
Medical hair loss restoration with these topical agents has the following outcomes:
- Slowed hair loss,
- Stabilization of hair loss
- Increased scalp coverage
Generally it takes about 3 to 6 months to see whether the medical hair loss restoration treatment is effective or not. Total results of medical hair restoration are clearly evident only after 1 year. Early intervention of the treatment, (when thinning is first noticed or the hairs are just becoming miniaturized), has shown to improve the outcomes of medical hair restoration treatment. But it is important to note that no medical hair restoration has so far been possible in areas of total hair loss (bald areas). In all the responders of hair loss restoration, treatment must be continued indefinitely to maintain the benefit. Stopping the medical hair restoration treatment with either minoxidil or finasteride results in a return to pretreatment status. The change over is evident within 6 months (for minoxidil) and 12 months (for finasteride).
Combination therapy for Hair loss restoration
Small-scale studies conducted on young men with mild to moderate MPHL suggest that combination therapy may be more effective than monotherapy. Medical hair loss restoration with the combination of both the fennerside and minnoxidal has been found to give optimum results in most of men.
Tretinoin (all-trans retinoic acid) a biologic response modifier is another possible option for medical hair restoration. It is a potent cell mitogen that promotes and regulates epithelial cell growth and differentiation. Tretinoin may have an effect on androgenetic alopecia by stimulating the growth of suboptimal hairs and it has been shown to act synergistically with minoxidil to produce more dense hair regrowth than either compound alone.
Medical hair loss restoration Vs Surgical hair loss restoration treatment
If condition of the patient with the above discussed medical hair restoration treatments does not stabilize after 1 year, or if the patient wants greater hair density, surgical hair restoration which involves hair transplantation or scalp reduction surgery may also be considered.
Hair restoration surgery under the age of 25 is not generally recommended because it is difficult to predict the ultimate extent and pattern of hair loss at that stage.
For patients with a more advanced condition of hair loss, medical hair restoration treatments are not very effective, and the surgical hair restoration is the only option left.
Hair transplant surgery can give good results only if the patient has a good donor area. If hair density is limited even after several hair transplantation procedures or the patient is in the advanced stage of hair loss, hairpieces are the only option left.
The hair loss restoration treatment management can be summarized as below:
1. Chantal Bolduc and Jerry Shapiro: ‘Management of Androgenetic Alopecia’,Am J Clin Dermatol 2000 May-Jun; 1 (3)
2. Elizabeth K. Ross, Shapiro: 'Management of Hair Loss', Dermatol Clin 23 (2005) 227 - 243