Common Causes of Hair Loss from the Scalp. Non Scarring Alopecias: A brief review of common causes of hair loss in men and women.
Hair loss, or alopecia, is a common and often emotionally distressing condition. Genetic predisposition, disease and improper hair care can all contribute to hair loss. They do so by increasing the rate of hair shedding (hair coming out by the root) or by increasing hair fragility leading to hair that can be broken by even minor trauma.
Depending on the cause, there are a number of treatments for scalp hair loss with varying degrees of effectiveness and patient satisfaction. This knol will discuss the typical hair cycle, as well as the various types of scalp hair loss and their associated treatments.
Hair Cycle
We are all born with about 100,000 hair follicles on the scalp. In a normal adult, approximately 90-95% of hairs in any given location are actively growing (anagen) and about 5-10% are in a resting state (telogen). Normal scalp hair grows about one-half inch per month. Hairs will remain in a resting state for about three to four months before being shed when a new hair emerges from the base of the follicle and the new hair “pushes” out the old hair. Each day, up to 100 “resting” hairs are shed from the head.[1] The amount of time a hair stays in the growth phase determines its length and the size of the hair bulb (that portion of the follicle which actively produces the hair) determines its diameter. Sometime to help diagnose the type of hair loss that occurs, physicians may perform a “pull test” where a small cluster of hairs is pulled firmly away from the scalp. If hair is dislodged, the roots can be examined to identify what stage of hair development they are in. This can often help establish what type of hair loss is occurring. To determine if the hair itself is damaged, a “tug” test may be performed where hairs are grasped at the base and center then gently tugged. If the hair is fragile or damaged, the hair will often break.
Hormones are important in regulating hair growth. For instance in puberty when hormone levels increase particular androgens such as testosterone change hair diameter and length. For instance, hairs in the beard, chest, and limbs enlarge but hairs in the temple region generally shrink.
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Figure 1: Diagram of a Hair Follicle
Common Causes of Hair Loss and Their Treatment
Androgenetic alopecia
Androgenetic alopecia (AGA) is a very common condition[2] and is due to progressive thinning of the hair caused by certain hormones called androgens. This condition occurs in men and women who have inherited the susceptibility but have normal levels of male hormones. Many affected individuals have family members with AGA. This condition is also known as male pattern baldness or female pattern hair loss.
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B.
Photos courtesy of V. Price
Figure 2: Androgenetic alopecia in men (A) and women (B).
The condition affects both men and women equally and begins between the ages of 12 and 40 years of age. Approximately half the population expresses some degree of hair loss due to AGA by the age of 50. In androgen-sensitive hair follicles of the scalp, normal levels of hormones cause hair to transform into progressively shorter and smaller diameter hairs with each successive hair cycle. Over time, only fine, miniaturized hairs remain leading to areas of scalp with decreased hair coverage. In men and women, certain patterns of hair loss are characteristic which helps establish the diagnosis. In men, hair loss in frontal/parietal scalp, top of the scalp (vertex) and bitemporal regions are typical. In women, thinning typically occurs on the frontal scalp although the frontal hairline remains intact. In AGA, the hair pull test is typically negative.
A small subset of women with female pattern hair loss may have an underlying hyperandrogen state such as polycystic ovary syndrome that can also cause menstrual irregularities and hirsutism (abnormal hair growth)[3]. Diagnosis of hyperandrogenism requires special hormone blood tests.
The goal of AGA treatment is to increase the coverage of the scalp and prevent further hair thinning. In the United States, oral finasteride (1mg per day) and 5% topical minoxidil solution or foam (applied twice per day) are currently the only drugs approved for promoting hair growth in men. A 2% minoxidil solution is approved for treatment of AGA in women (applied twice a day). Both drugs can increase coverage of the scalp by enlarging existing hairs, and both retard further thinning. However, neither drug restores all hair and responses will vary from individual to individual. In addition, neither drug will benefit totally bald individuals.
Finasteride limits further hair loss in 70-80% of male patients. When used for at least two years, 66% of men experienced a 10-25% regrowth of hair[4]. Side effects are rare but include decreased libido and erectile dysfunction in 1.8% of recipients.
Minoxidil has also been shown to be effective in several studies. For instance, after 2.5 years, 54% and 48% of patients using minoxidil 5% and 2% solutions, respectively, showed increased hair counts[5]. Side effects include rash in 6.5% of patients or growth of unwanted facial hair in 3-5% of women.
In general, treatment with either medication is necessary for about 12 months to improved scalp coverage. If either medication is discontinued, all benefits are lost within one year so continued treatment is needed to maintain benefit. Those patients who respond to treatment require treatment indefinitely. Minoxidil and finasteride can be combined to increase hair regrowth.[6] Minoxidil is available over the counter and can be purchased in most drug stores. Finasteride requires a prescription from a physician.
When hair thinning is extensive, men and some women may consider hair transplantation, a surgical procedure that involves moving hair from hair-bearing sites of the head (donor site) to the areas of thinned hair (recipient site). Alternatively, surgery may sometime be performed to remove bald areas of scalp altogether (scalp reduction surgery). Surgical treatment can be combined with finasteride or minoxidil to improve results of surgery.
Hair addition devices can be attached to existing hair to give the appearance of a fuller head of hair. Hair weaves, hair extensions, hair pieces, toupees, non-surgical hair replacements, partial hair prostheses, or hair wefts are all examples of these types of devices. Devices may consist of human hair, synthetic fiber or a combination of both. In addition to hair addition devices, there are a variety of “cover-up” products that can be applied to the scalp or to hair in the thinned areas to mask visible scalp and create the illusion of thicker and fuller hair.
To learn more about:
- Hair loss in general, see http://www.hairlossexpert.co.uk/
- Hair restoration surgery, see http://www.ishrs.org/
- Hair addition devices, see http://www.ahlc.org/solutions-nons.htm
- Hair “cover-up” products, see http://www.hairtransplantnetwork.com/Hair-Loss-Treatments/thickners.asp
Telogen effluvium
Telogen effluvium is the diffuse shedding of hair that occurs two to three months after a severe bodily stress[7]. The stressful event causes premature and simultaneous shift of a large numbers of hair follicles from the growth phase (anagen) to the resting phase (telogen) of the hair cycle. When the stressor has passed and hair resumes normal growth (1 to 6 months later, shedding of all the extra “resting” hairs occurs simultaneously causing an abrupt and dramatic increase in the number of shed hairs. Telogen effluvium is generally not extensive enough to cause noticeable decreased hair density and the hair loss occurs throughout the scalp in contrast to the pattern loss seen in AGA. In active telogen effluvium, the pull test is positive for multiple hairs in the resting (telogen) phase.
Causes of telogen effluvium include the following:
1. High fever
2. Childbirth
3. Severe infections
4. Major surgery
5. Crash diets, poor nutrition, inadequate protein
6. Severe psychological stress
7. Thyroid abnormalities
8. Medications
9. Malignancy
Categories of medications than may cause telogen effluvium include:
1. Anticancer drugs
2. Anticonvulsants
3. Anticoagulants
4. Antigout medications
5. Antithyroid medications
6. Beta-adrenergic blockers
7. Tricyclic antidepressants
8. Oral contraceptives
The condition is usually self-limited and treatment of the underlying bodily stress generally results in hair regrowth in 1 to 6 months after the underlying condition is corrected.
Alopecia areata (AA) is an autoimmune disease that affects almost 2% of the US population, including more than five million people in the United States alone[8]. In alopecia areata, the affected hair follicles are mistakenly attacked by a person's own immune system (white blood cells), resulting in the arrest of the hair growth stage. Alopecia areata usually starts with one or more small, round, smooth bald patches on the scalp and can progress to total scalp hair loss (alopecia totalis) or complete body hair loss (alopecia universalis). Any hair-bearing site on the body can be affected by alopecia areata. Hair loss can often occur without any accompanying symptoms. When the pull test is positive at the borders of an affected hair patch, the immune response against hair follicles is actively occurring.
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Although AA affects both sexes equally and occurs at all ages, children and young adults are affected most frequently. Patients with early onset (less than 30 years of age) often have other family members with AA (10-42%) and episodes of hair loss may last longer than patients who develop the disease at an older age (more than 30 years of age). Spontaneous hair regrowth and recurrent patchy hair loss is common at all ages and predicting the course of the disease is difficult. Recovery can be complete or partial; when scalp involvement is limited (less then 25% scalp involvement), 90% of patients will have spontaneous regrowth within two years[9]. This group also generally responds well to treatment. Alopecia totalis or alopecia universalis that lasts longer then two years has a low chance of spontaneous regrowth and is less responsive to therapy. The important point is that the potential for regrowth is always there, and the possibility of a recurrence is also always there.
Patients with AA are usually otherwise healthy, but autoimmune thyroid disease, vitiligo (loss of skin pigmentation), and atopy (asthma, eczema or hay fever) are more common among AA patients then in the general population. Patients with AA may also develop rows of shallow pits that occur on the surface of fingernails. The presence of severe nail abnormalities, atopy, and onset of extensive hair loss at less than five years of age may mean these patients will have more severe and long lasting disease than others.
Patients with AA are treated with anti inflammatory medications such as injected cortisone or hair growth stimulators such as minoxidil. The choice of therapy depends primarily on the patient’s age and extent of hair loss (see Table 1). Therapy should be continued until remission occurs or until residual patches of alopecia are concealed by regrown hair which may take months or years. The most common treatment in adults is intralesional injected cortisone. The concentration of cortisone will vary from treatment site, but typically the medication is injected in 0.5 to 1.0cm intervals within the patches of bare scalp. Side effects of treatment may include local pain from the injection, bleeding, persistent redness and small indentations corresponding to the injection sites.
Table 1: Treatment for Patients with Alopecia Areata According to Age and Severity of Condition[10]
Patients ≤ 10 years of age
- 5% Topical minoxidil solution, topical glucocorticoid, or both
- Anthralin (short contact)
Patients ≥ 10 years of age
<50% of scalp affected
- Intralesional glucocorticoid, 5% topical minoxidil solution, or both
- Anthralin (short contact)
≥50% of scalp affected
- 5% Topical minoxidil solution
- Topical immunotherapy
- Anthralin (short contact)
- Oral glucocorticoid
- Scalp prosthesis
Eyebrow and beard affected
- Intralesional glucocorticoid, 5% topical minoxidil or both
The National Alopecia Areata Foundation (http://www.naaf.org/default2.asp) is an organization that offers a wealth of educational information to patients and their families. In addition, clinical studies are currently underway and patients interested in enrolling should contact the National Alopecia Areata Foundation. Patients interested in the NIH-funded National Alopecia Areata Registry should enroll online at http://www.alopeciaareataregistry.org. The Foundation also provides an annual patient conference, a network of support groups across the country, and a quarterly newsletter.
For children with alopecia areata, the Children’s Alopecia Project (http://www.childrensalopeciaproject.org/cap/index.php) is a non profit organization devoted specifically to children with this disease.
Hair Loss Due to Oral Contraceptives
Some oral contraceptives or hormone replacement regimens can have high levels of androgens or androgen precursors which cause women predisposed to androgenetic alopecia to undergo hair thinning. Consult with your gynecologist or primary care physician to evaluate if the oral contraceptive you are using may be related to hair loss.
Metabolic Causes
Thyroid disease: Both an over-active thyroid and an under-active thyroid can cause hair loss. Symptoms of an over-active thyroid include heat intolerance and a new tremor. Symptoms of an under-active thyroid include cold intolerance and constant fatigue. Your physician can diagnose thyroid disease with laboratory tests. Hair loss associated with thyroid disease can often be reversed with treatment of the thyroid disease.
Iron deficiency anemia occasionally produces hair loss but more commonly can exacerbate an ongoing hair loss condition. Women who have heavy menstrual periods may develop iron deficiency. Iron deficiency anemia can be diagnosed by your physician with laboratory tests. Iron deficiency can be corrected by taking iron supplements.
Syphilitic Alopecia
Syphilis is an infectious sexually transmitted disease that can cause sudden onset, patchy, incomplete hair loss often described as “moth eaten” hair loss three to five months after infection. Eyebrows, eyelashes and beard may also be lost. A blood test may be performed to identify a syphilis infection. Syphilis treatment is with oral antibiotics.
Loose anagen syndrome is a condition where normal (anagen) hairs are loosely anchored in the scalp and can be easily and painlessly pulled from the scalp. This condition is usually diagnosed in children who are otherwise normal but have sparse hair that seldom needs to be cut. The hair density and length improve with age but the looseness persists for life. The condition may also be associated with rare genetic syndromes that cause developmental defects. There is no medical treatment for loose anagen syndrome.
Fungal infection (Tinea capitis)
Tinea capitis is a fungal infection of the scalp that occurs most commonly in children. In fact, it is the most common cause of hair loss in children between ages two and 10 years. The infection can take on a variety of appearances from raised, circular scaly scalp patches to highly inflamed, weeping areas with partial hair loss and scattered broken hair stumps. The fungus invades the hair causing the hair shaft to weaken and be easily broken at the sites of invasion.
The infection can be diagnosed a variety of way including skin scrapings, cultures of affected hair or by examining scalp hair for fungus under a microscope. Before 1970, many cases of tinea capitis were caused by the Microsporum species of fungus which could be transmitted by pets, however most cases today are caused by Trichophyton tonsurans which is passed from one person to another through direct contact, fallen infected hairs, or use of contaminated hairbrushes, combs or hats. Tinea capitis is treated by oral antifungal agents such as griseofulvin, terbinafine, itraconazole, or fluconazole. Once a course of treatment is completed, hair regrowth occurs within one to three months.
Trichorrhexis Nodosa
Trichorrhexis nodosa is the most common hair shaft fracture. This condition is the common end result of various practices that damage the hair shaft resulting in brittle, fragile hair that is easily broken. Affected areas of scalp have patches of hair of varying length. The tug test is positive which indicates damage along the hair shaft rather than the hair follicle. When observed under a microscope, the affected hair will have frays and splits at multiple sites along the length of the hair fiber. This breakage is seen most often in African-American women, but Caucasians and Asians may also develop this type of breakage.
A variety of hair care practices and exposures including excessive brushing, exposure to sun, hot combs and hot rollers, hair straightening with chemical or with heat may lead to trichorrhexis nodosa. To treat this condition, affected hair must be handled gently and any manipulation of hair that causes additional damage should be avoided. Conditioners may help nurture damaged hair that make the hair softer and less brittle are helpful. Recovery may take from two to four years.
Anagen Arrest Anagen arrest is hair breakage caused by chemotherapy medications (see Table 2). These drugs halt the normal growth of hair resulting in a narrowing of the hair shaft. When the narrowed hair shaft reaches the skin surface, usually in about two weeks, the narrowed hair shaft breaks off at the scalp surface. About 80-90% of hair will break simultaneously. This condition is reversible, and hair will regrow after chemotherapy is completed. Patients starting chemotherapy with agents known to cause anagen arrest should be forewarned and hair wraps or wigs should be prepared ahead of time.
Table 2: Common Chemotherapy Agents the Cause Anagen Arrest
- Bleomycin
- Cyclophosphamide
- Cytarabine
- Doxorubicin
- Fluorouracil
- Hydroxyurea
- Methotrexate
- 6-Mercaptopurine
- Vincristine
To learn more about hair loss during chemotherapy see:
To learn more about head covers and wigs for patients undergoing chemotherapy contact the American Cancer Society at (800) 543-5245. The American Cancer Society and the National Breast Cancer Association both support programs that provide wig or hair prosthesis programs to patients with limited financial means.
To learn more:
- National Breast Cancer Association, http://www.y-me.org/programs/wig_and_prosthesis_bank.php
For children undergoing chemotherapy who need hairpieces:
- http://www.locksoflove.org/apply.html
Traction Alopecia
Traction alopecia is a form of traumatic hair loss common in girls and women whose hairstyles involve tight ponytails, plaits, braids or hair extensions that keep the hair under constant traction for prolonged periods. Over time, constant pulling causes hair breakage and hair follicle damage. If prolonged, the hair follicle may not recover and permanent hair loss may result. The mainstay of treatment is to discontinue hairstyling that results in pulling on the traumatized hair.
Trichotillomania
Trichotillomania is a disorder in which persons compulsively pull, twist or break their own hair. It occurs most frequently in girls and women and is more common in young persons. Sometimes skin picking or nail biting or other obsessive compulsive-type disorders may also be present. The scalp is the most common affected site, followed by the eyebrows, upper eyelashes, pubic hair, trunk and extremities although any hair-bearing area may be affected. The affected areas have bizarre, angulated shapes with short broken hairs of varying lengths, and without any scale. To learn more about his disorder see http://www.trich.org/index.asp
Acknowledgements:
Special thanks to Drs. Deborah Sah and Vera Price from University of California, San Francisco for their thoughtful review and contribution of clinical photographs
References:
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[2] Otberg N, Finner AM, Shapiro J. Androgenetic alopecia. Endocrinol Metab Clin North Am. 2007 Jun;36(2):379-98.
[3] Ross EK, Shapiro J. Management of hair loss. Dermatol Clin. 2005 Apr;23(2):227-43.
[4] Whiting DA, Olsen EA, Savin R, Halper L, Rodgers A, Wang L, Hustad C,Palmisano J; Male Pattern Hair Loss Study Group. Efficacy and tolerability of finasteride 1 mg in men aged 41 to 60 years with male pattern hair loss. Eur J Dermatol. 2003 Mar-Apr;13(2):150-60.
[5] Koperski JA, Orenberg EK, Wilkinson DI. Topical minoxidil therapy for androgenetic alopecia. A 30-month study. Arch Dermatol. 1987 Nov;123(11):1483-7.
[6] Arca E, Açikgöz G, Taştan HB, Köse O, Kurumlu Z. An open, randomized, comparative study of oral finasteride and 5% topical minoxidil in male androgenetic alopecia. Dermatology. 2004;209(2):117-25.
[7] Han A, Mirmirani P. Clinical approach to the patient with alopecia. Semin Cutan Med Surg. 2006 Mar;25(1):11-23.
[8] Price VH. Treatment of hair loss. N Engl J Med. 1999 Sep 23;341(13):964-73.
[9] Hordinsky MK. Medical treatment of noncicatricial alopecia. Semin Cutan Med Surg. 2006 Mar;25(1):51-5.
[10] Price VH. Treatment of hair loss. N Engl J Med. 1999 Sep 23;341(13):964-73.