By Maria Mozo
Perhaps, one of the feared eventualities of late adulthood is alopecia. Alopecia is the medical term for the partial or complete loss of hair from the body (especially from the head). In simple terms, alopecia is hair loss or baldness. According to U.S. National Library of Medicine (NLM), by the age of 50, hair loss leading to a well-defined pattern of baldness is likely to affect about 50 percent of all men. 1 Hair loss leads to a receding hairline that eventually forms a characteristic M shape. In some men, the thinning of hair begins near the top of the head, and may progress to partial or complete baldness. 1 This male-pattern baldness is referred to as androgenetic alopecia. It is more obvious in aged men than aged women. In women, there is no hairline recession but hair thinning, which is diffuse. Alopecia in women is called female androgenetic alopecia (or female-pattern baldness).
Apart from androgenic alopecia, there is another form of alopecia, i.e. alopecia areata. This type of alopecia is caused by an autoimmune disease. By autoimmune, it means the body fails to recognize its own cells. As a result, the immune system destroy own cells as if they were microbes or foreign cells. In alopecia areata, the body’s immune system attack its own hair follicles, and therefore cause bald patches on the scalp. Similar to the male-pattern baldness, the alopecia areata is heritable.
Although genetic factors come into play, there are other factors triggering alopecia. One of them is malnutrition. Insufficient biotin, zinc, and proteins in the diet as well as a diet rich in animal fats (e.g. those in fast food) and vitamin A (hypervitaminosis A) may lead to hair loss. Another factor is the intake of certain pharmacological drugs, e.g. anabolic steroids, contraceptive pills, chemotherapeutic drugs, arthritis drugs, anticoagulants, anticonvulsants, amphetamines, antidepression drugs, cholesterol-lowering drugs, beta-blocker drugs, and drugs used to treat indigestion, stomach problems, and ulcers.2
Topical treatments containing minoxidil may help stop hair loss and promote hair growth. However, minoxidil is not for everyone. It is less effective to those with an extensive hair loss. The mechanism of action of minoxidil is limited. It can only stimulate hair follicles and hair growth but it does not act on the dihydrotestosterone around the hair follicle. Dihydrotestosterone (DHT) is said to be the primary contributing factor in androgenetic alopecia. 3 Produced by 5α-reductase enzyme, DHT gets to the dermal papilla (i.e. the hair part that forms new hair follicle) and subsequently impairs the absorption of nutrients needed in forming new hair follicle. Without an adequate nutrition, the hair follicle goes through longer resting stage than growing phase, and therefore shorter lifespan. Finasteride, an oral drug recommended for alopecia, acts on DHT by reducing its sysnthesis. However, there were reports indicating sexual dysfunction as an adverse effect. 3 This might be due to the action of the drug on DHT synthesis within the body since the drug is administered orally.
A research team from Columbia University Medical Center recently introduced two drugs for alopecia that might prove more effective and safer . The team was able to find a way to block a family of enzymes (i.e. Janus kinase family, JAK) inside the dormant hair follicles. Blocking these enzymes promoted hair re-growth in their mouse experiments. These drugs containing JAK inhibitors have been given FDA approval and may be used topically for managing alopecia. Further studies though are still under way to determine the efficacy of these drugs as well as possible side effects in humans. 4
1 U.S. National Library of Medicine (NLM). (2015). Androgenetic alopecia. Retrieved from http://ghr.nlm.nih.gov/condition/androgenetic-alopecia.
2 Drug-Induced Hair Loss.WebMD.com. Retrieved from http://www.webmd.com/skin-problems-and-treatments/hair-loss/drug-induced-hair-loss-1?page=1.
3 Nordqvist, C. (2012). "What Is DHT (Dihydrotestosterone)? What Is DHT’s Role In Baldness?". Medical News Today. Retrieved from http://www.medicalnewstoday.com/articles/68082.php.
4Columbia University Medical Center. (2015, October 23). Blocking enzymes in hair follicles promotes hair growth: Two FDA-approved drugs reawaken dormant hair follicles. ScienceDaily. Retrieved from www.sciencedaily.com/releases/2015/10/151023174914.htm.