Androgenetic Alopecia: Cause of 95% of all hair loss
Androgenetic alopecia or pattern baldness is the most common cause of hair loss is pattern loss, which eventually affects over 70% of men and 15% of women. In classic pattern, hair thins in a horseshoe pattern, although more diffuse loss can also occur.
At least two sequential processes contribute to pattern loss, which begins as an abnormal sensitivity of the hair follicles to androgens of male sex hormones. In most people, this is followed by a local immune reaction to the affected hair follicle, which further damages it and is probably responsible for its eventual death.
Both men and women experience androgenetic alopecia, or pattern hair loss, although men generally experience a much greater degree of loss. In men, the pattern of loss starts with the hairline or back of the head, advances to thin the top of the head, and often leaves just a fringe of hair extending from ear to ear across the back of the head and affects the thinner, shorter, and less pigmented hairs of the frontal and parietal portions of the scalp.
In women, pattern loss tends to be more diffuse, and occurs over a broader area. Women usually do not have bald spots, but rather have overall thinning hair. In diffuse hair loss in men or women, over 50% of the hair can be lost before the results are readily apparent.
Alopecia areata, the second major cause of hair loss, generally appears as patchy loss but may also occur as alopecia totalis, which involves the entire scalp, or as alopecia universalis, which involves the entire body.
It occurs most frequently in young and middle-aged adults of both sexes. Although mild erythema may occur initially, affected areas of scalp or skin appear normal. This may be anywhere on the scalp or even the rest of the body.
Alopecia areata is also an autoimmune disease but without the normal hormonal component in pattern loss. In simple terms, white blood cells attack the hair roots resulting in loss of hair.
About 30% of individuals with this problem are aware of a relative with this disorder; thus, there seems also to be a genetic component. At times, scarring (cicatricial) alopecia follows scar tissue formation resulting from inflammation and tissue destruction.
A variety of approaches are currently used for treatment; all are aimed at interrupting the "attack" of white blood cells upon the hair roots.
The major therapies include topical and locally injected corticosteroids; topical minoxidil along with anthralin; various topical irritants or sensitizers; special light treatments (called PUVA); and a number of experimental drugs which alter the immune system.
It cannot be accurately predicted when the condition may become occur. An episode might be precipitated during a illness or a physiologic stress. This type of hair loss may recur at any time.
New patches of hair loss can develop while older patches are being effectively treated. Sometimes hair will regrow spontaneously over a period of months to years - this is less likely with more extensive hair loss.
The areas of hair loss often have spontaneous hair regrowth. The new hair may initially be non-pigmented, with pigment production resuming at a later. Intralesional corticosteroid injections are beneficial for small patches and may produce regrowth in 4 to 6 weeks.
This condition is not transmitted by contact with a person who has it - it is not contagious.
Other Causes of Hair Loss
Nutritional deficiencies must be severe to cause hair loss. In situations where hair loss is the result of a nutritional deficiency, other more serious symptoms are usually evident. Nutritional treatments for hair loss are only effective in the rare situations where a nutritional deficiency actually exists.
A deficiency of iron can results in anemia or a reduced amount of red blood cells, and this can contribute to hair loss. Anemic people generally appear pale and weak.
Trauma and Burns
Trauma to hair follicles can result in permanent hair loss. Thermal and chemical burns for example, can kill hair follicles and result in hair loss. Hair straighteners can cause follicle damage and produce serious hair loss.
Thyroid gland irregularities cause hair loss. There is no way to predict which patients will experience hair loss, which will not, and who will be severely affected and who will have only minimal hair loss.
Excessive thyroid hormone production is a condition called hyperthyroidism which results in thin soft hairs that are easily extracted, along with other symptoms.
An under-active thyroid gland causes thyroid hormone deficiency, called hypothyroidism which results in coarse lifeless hairs, that are also easily extracted, along with other symptoms.
Fortunately, hair loss from hyperthyroidism or hypothyroidism is usually reversible with proper treatment of the thyroid condition. Typically hair loss does not immediately stop when the blood work becomes normal.
Most people stop losing their hair and begin replacing lost hair a few months after the thyroid hormone levels become normal.
Stress can contribute to hair loss. Thyroid disease can have a direct impact on the psychological well-being of patients, particularly under stress.
Often as patients become more concerned about their hair loss, their stress levels increase, making the situation worse.
Because of the often fragile condition of the scalp and hair follicles, one must be cautious when considering chemical treatments for hair such as coloring or permanent waves.
Cutting the hair shorter, using moisturizing and conditioning hair products, and avoiding back combing decrease stress on the hair.
Physiologic alopecia is the sudden hair loss in infants, loss of straight hairline in adolescents, and diffuse hair loss after childbirth. It is usually temporary.
Trichotillomania is the compulsive pulling out of one's own hair. It is most common in children. In trichotillomania, patchy, incomplete areas of hair loss with many broken hairs appear primarily on the scalp but may occur on other areas as well, such as the eyebrows.
In trichotillomania, an occlusive dressing encourages normal hair growth, simply by calling attention to the problem (and to the possible need for psychiatric counseling).
Predisposing factors of non-scarring alopecia also include radiation, many types of drug therapies and drug reactions, bacterial and fungal infections, psoriasis, seborrhea, and endocrine disorders, such as thyroid, parathyroid, and pituitary dysfunction.
Scarring alopecia causes irreversible hair loss. It may result from physical or chemical trauma, or chronic tension at the hair shaft, such as braiding or rolling the hair.
Diseases that produce alopecia include destructive skin tumors, granulomas, lupus erythematosus, scleroderma, follicular lichen planus, and severe bacterial or viral infections, such as folliculitis or herpes simplex.
Common Drugs, Chemicals, and Conditions that Cause Hair Loss
(Telogen effluvium or toxic effluvium)
At times, hair is lost due to stresses, poisons or medical conditions. Hair loss was reported in patients during the 1918 flu epidemic. The characteristic feature of this type of hair loss is a latent period of several weeks between the inciting event and clinical hair loss.
There is a greater sensitivity of actively growing (anagen) hairs, in contrast to resting hair, to a variety of toxic chemical or physical agents. Indeed, x-ray epilation to rid the scalp of fungus infections was standard therapy. The accidental exposure to poisons or natural products also may cause hair loss. Some cosmetics have produced hair loss.
Agents for gout: Allopurinol (Loporin, Zyloprim)
Anticoagulants (Blood thinner): Coumadin and Heparin
Anticonvulsants for epilepsy: trimethadione (Tridione)
Antidepressants: tricyclics, amphetamines
Antiarthritics: penicillamine, auranofin (Ridaura), indomethacin (Indocin), naproxen (Naprosyn), sulindac (Clinoril), and methotrexate (Folex)
Antithyroid agents: carbimazole, Iodine, thiocyanate, thiouracil
Beta blocker drugs for high blood pressure: atenolol (Tenormin), metoprolol (Lopressor), nadolol (Corgard), propranolol (Inderal) and timolol (Blocadren)
Cancer chemotherapy medications (many)
Cholesterol-lowering drug: clofibrate (Atromid-S) and gemfibrozil (Looped)
Drugs derived from vitamin: Tretinoin (Actuate) and etretinate (Tegison)
Male hormones (anabolic steroids)
Parkinson medications: levodopa (Doper, Larodopa)
Ulcer drugs: Cimetidine (Tagamet), ranitidine (Mantic) and Cimetidine (Pepped)
Plants and Foods
Ingestion of the nuts of the monkey pot tree, cocoa de mono (Lecithin Collabra) a deciduous tree widely distributed in Central and South America.
Plants such as Stanley, Astragals pectinatus (locoweed), Lacuna, Mellitus (yellow sweet clover), Colchicum autumnal, Glorious, and Saptaceae (several Brazilian woods of this family).
The amino acid analog, mimosine, from the seeds of the shrubby tree Leucaena glauca. This species is widely established in Hawaii (where it was once planted as fodder for grazing animals) and can be found growing wild in southern Florida.
Salts of lithium, lead, mercury, selenium, bismuth, arsenic, thallium, and borates
Coroprene dimers used in the synthetic rubber industry
Medical Conditions or treatments
In women after giving birth to a child
Discontinuation of oral contraceptives
Radiation: x-rays neutrons, alpha particles
Hair Mites (Demodex Folliculorum)
Demodex is a narrow, wormlike mite that lives in the hair follicles of the scalp, eyelashes, nose and chin of most adults. No one knows what role it plays in hair follicle health although there have been unproved claims that it may cause hair loss.
Certain persons with very reactive immune responses to the mite may suffer hair loss from its presence. However, as with the skin's natural bacteria, it may keep away more harmful parasites.
Dr. William Regelson, of the Medical College of Virginia has recently proposed (February 1998) that Demodex is implicated in hair loss.
He speculates that people who eventually lose their hair and those who do not, however, likely depends on whether the scalp produces an inflammatory reaction in an attempt to reject the mite.
A researcher at Nioxin, a hair-care and cosmetics developer based in Lithium Springs, GA has recently claimed the discovery of Demodex. However, Demodex was first described in 1842, has been the subject of many studies.
While Demodex is associated with many skin conditions, most researchers have concluded that the mite is not a major factor in hair loss. The patterns of hair loss do not correspond with Demodex populations.
However, excessive mites have been associated with loss of eyelashes (Demodex blepharitis).
A 1996 study from the Department of Laboratory Medicine, VA Medical Center in North Carolina, published the results of a found an association between mite populations in the hair follicle and scalp inflammation.
Demodex mites were found in over 40% of follicles with inflammation, but in just 10% of the follicles without inflammation. However, the researchers could not conclude whether Demodex caused the inflammation or preferentially colonized inflamed follicles.
A 1995 study by the Academy of Sciences of the Czech Republic concluded that while Demodex tend to colonized in the lumen of hair follicles, they do not cause any noticeable pathological conditions.
The most common conditions associated with Demodex is a swelling of the colonized hair follicle. This normally requires up to a dozen mites for swelling to take place but many infested follicles showed no swelling.
Skin conditions associated with Demodex can be easily treated by topical medication. Medications include gentamicin sulfate, an ointment of a 0.5% selenium sulfide cream, 4% pilocarpine gel, an ointment of 10% sulfur and 5% balsam and a gel of 4% pilocarpine gel.
Pilocarpine gel is directly toxic to the mites by constricting their bronchioles and suffocating them. Nioxin sells a Semodex line of products formulated Demodex infestation. The Semodex line of products is available in many hair salons in the US or send an e-mail to HairSite@aol.com if you have trouble locating Semodex in your area.