Male Pattern Baldness: Causes and Treatments
Male pattern baldness (MPB, also male pattern hair loss or androgenetic alopecia) is a hereditary condition characterized by a receding hairline and the disappearance of hair from the crown area of the head. The loss of hair progresses gradually throughout a man’s lifetime and it may eventually affect the entire top of the scalp. The lower back and sides of the scalp usually remain unaffected. MPB is the most common type of hair loss in humans, affecting nearly 50% of men over age 50.
Each person is born with a set amount of hair follicles, growing around 100,000 hairs. A normal person loses up to 30% of their hair by middle age, which goes largely unnoticed. Male pattern baldness is not noticeable until at least half of the hairs in a given area have been lost. Hair thinning is a part of the balding process when hair is not yet completely lost but it has lost its original thickness and color due to a process called hair miniaturization.
Causes of Male Pattern Baldness
The main risk factor for male pattern baldness, also known as hereditary hair loss, is, as the name suggests, heredity. Besides genetic predisposition to MPB, other major factors include the action of androgens (male sex hormones), ethnicity and increasing age. Male pattern hair loss is most common in Caucasians, with the lowest rates of incidence occurring in Native Americans and Asians.
Dihydrotestosterone (DHT), a natural metabolite of the male hormone testosterone, is considered to be the main organic cause of MPB. DHT causes shrinkage of the susceptible hair follicles, which respond by producing thinner, shorter and finer hair with each growth cycle until they eventually stop producing hair altogether. We do not know yet why only some follicles in some people are susceptible to DHT. DHT also happens to be the cause of benign prostatic hyperplasia (BPH) and studies have shown that men who lose their hair before they turn 30 have an increased risk of developing BPH.
Signs of Male Pattern Baldness
Male pattern baldness is usually noticeable by visual examination. It may begin shortly after puberty and is typically first noticeable around the temples (as receding hairline) and crown area. The areas affected first may vary from person to person. A transition from thick, long, colored terminal hairs to thinner, shorter, colorless vellus hairs typically occurs gradually. As a result, MPB may not be apparent to the naked eye until significant thinning has occurred.
Hair loss, if caused by male pattern baldness, is not usually a cause for health concern. However, sudden, rapid hair loss can be an early sign of certain illnesses such as diabetes, hyperthyroidism, hypothyroidism, systemic lupus erythematosus, etc. Hair loss may also develop as a result of poor nutrition (e.g. vitamin B or iron deficiency) or as a side effect of certain medications. If you experience sudden, rapid hair loss or hair loss in patches or you begin losing hair shortly after starting a new medication or you develop hair loss together with other symptoms, such as skin irritation, redness, itching, scaling or pain, consult a dermatologist.
Diagnosing Male Pattern Baldness
Male pattern baldness is diagnosed by analyzing the total amount of hair on the scalp and its distribution. Densitometer is commonly used to assess the degree of miniaturization of the hair follicles. Men with MPB typically start losing hair on the top of the scalp and around the temples, making diagnosis relatively routine. The Hamilton-Norwood classification chart, which breaks down the progression of MPB into seven classes, is used to determine the degree of hair loss.
Additional testing may include skin biopsy (to exclude poison-induced hair loss) and blood tests to check if certain conditions that commonly cause hair loss, such as iron deficiency, hyperthyroidism or hypothyroidism, may be present. Side effects from certain medications, such as antidepressants, anticonvulsants, anticoagulants and beta blockers, may also induce hair loss and should therefore be considered.
Treating Male Pattern Baldness
There is no cure that could reverse hair loss. Treatment of MPB focuses on maintaining the existing hair and increasing its fullness. Two medicinal drugs have been approved by the FDA to treat male pattern hair loss:
Minoxidil (Rogaine) is a topical treatment containing 5% of minoxidil that comes in the form of a solution, gel or foam. Minoxidil is a vasodilator that has been found to stimulate hair growth. It works by promoting the larger hair shaft diameter and prolonging the hair’s growth phase. This treatment, as any other treatment for hair loss, must be used for as long as you wish to maintain your hair. Minoxidil works best in the crown area of the scalp. Side effects commonly associated with topical minoxidil include irritation of the scalp, increased hair growth on other parts of the body, fast or irregular heart rate and swelling of lower legs. Topical minoxidil is available over-the-counter.
Finasteride (Propecia) is a once-daily pill that works by inhibiting type II and III 5-alpha reductase, which is the enzyme that converts male hormone testosterone in follicle-shrinking dihydrotestosterone (DHT). Finasteride was originally used to treat benign prostatic hyperplasia which has the same cause as MPB. By reducing the levels of available DHT in the body, finasteride protects the hair follicles from further miniaturization and, like minoxidil, works best in the crown area of the scalp. The most common complaints of patients using this drug include weight gain, sexual side effects and tenderness and enlargement of the breast. Propecia (finasteride) is only available on prescription. Pregnant women may not come in contact with finasteride as it may cause birth defects in male babies.
Dutasteride (Avodart) is an oral medication sometimes prescribed to treat MPB, though it has not yet been approved by the FDA for treating this condition (it is currently approved for treating BPH and prostate cancer). It belongs to the same class of drugs as finasteride but it inhibits all types of 5-alpha reductase (I, II and III). Dutasteride has been through all phases of clinical testing for treating hair loss and results were quite encouraging. But, because of its long half-life, it stays in the bloodstream for much longer than finasteride and its potential side effects can be felt months after discontinuing the treatment. This is believed to be the main reason why GlaxoSmithKline has not yet requested its approval for MPB. Despite that some doctors prescribe dutasteride off-label to their long-term hair loss patients who no longer respond to finasteride.
Hair transplantation is the most suitable treatment option for hair loss patients who would like to see more noticeable cosmetic results than those achieved with medications. Hair transplantation consists in extracting and moving healthy hair follicles from the back of the scalp to the balding area. Follicular unit extraction is the most popular technique used today, though for patients with extensive baldness some clinics will still recommend a less expensive and more efficient follicular unit transplantation (good old strip technique). Common risks and complications associated with hair surgery include postoperative bleeding and scarring, poor hair growth in transacted hair follicles, numbness and tension in the scalp and the risk that the patient will not like his new look. Hair surgery does nothing to stop further hair loss, therefore, the patient will have to continue with his medical treatment.
Alternative treatments. There is an array of unproven hair loss treatments, many of them of herbal origin. Some of them, like saw palmetto, stinging nettle root, pygeum africanum, green tea extract, procyanidins, plant-derived essential fatty acids or beta-sitosterol, are believed to mimic the actions of 5-alpha reductase inhibitor drugs and thus protect hair follicles from shrinking. Others, such as ginkgo biloba, azelaic and retinoid acid, caffeine, superoxide dismutase, copper peptides, methylsulfonylmethane (MSM), laser comb and scalp roller, should stimulate new and improved hair growth by promoting blood flow to the scalp as well as by many other different ways. But, keep in mind that none of these remedies has been tested and approved by the FDA for treating male pattern baldness.