Many people wonder what causes hair loss. The causes of hair loss vary depending on a number of factors, including genetics (this is often what causes baldness or alopecia), illness (such as thyroid disease), and medications you may be taking. The best way to uncover hair loss causes and find out whether they are preventable is to see a physician.
What causes hair loss in men and women is also related to lifestyle. Factors such as stress, exposure to chemicals or UV rays, smoking and consuming alcohol can play a role in triggering or exacerbating the loss of hair (and can also affect recovery from hair restoration surgery). It is also important to be aware that certain types of hairstyles, including braids, tight ponytails and hair extensions, can cause tension and trauma to the hair follicle, leading to hair loss.
This is the most common form of hair loss in men, with a lifetime risk of 50-70% of all males depending on the quoted study. It is characterized by miniaturization of scalp hairs, where thick terminal hairs are replaced by finer, thinner versions of themselves.
Also, there is decreased time spent in the anagen (“growth”) phase and increased time spent in telogen (“resting”) phase of the hair cycle. The result is the appearance of thinner hair that is decreased in size and number of follicles.
This condition typically runs in families. Classification of male pattern hair loss is often described using the Hamilton-Norwood Scale of hair loss, which stratifies severity based on area of involvement and extent of hair loss. Most commonly, men experience hair loss in the frontal hairline and vertex (crown) of the scalp. Though this condition is often distressing to patients, many medical and surgical treatment options are available. Currently, the only FDA approved medications for male pattern hair loss are topical minoxidil and oral finasteride. Various low-level light therapy (LLLT) devices are FDA cleared for use in treating androgenetic alopecia. Other off-label options include oral dutasteride, topical finasteride, oral minoxidil, and platelet-rich plasma. Hair restoration surgery can provide patients with a more permanent and dramatic solution. Camouflaging agents are also quite popular and effective.
This condition is analogous to what is experienced in men, and is also the most common cause of hair loss in women. It also results from hair miniaturization. However, while men tend to experience hair loss in the frontal hairline and vertex, women usually retain their frontal hairline and instead have a loss of density in the frontal one to two-thirds of the scalp.
It is classified according to the Ludwig Scale I-III, and has also been described as occurring in a “Christmas Tree” pattern with widening of the part toward the front. Some women may have very diffuse thinning all over.
As in male pattern hair loss, this condition is very treatable using a combination of medical and surgical approaches. For women, topical minoxidil is the only FDA-approved medical therapy, but other medications including spironolactone, oral contraceptives, finasteride and dutasteride are used with great success. Low-level light therapy (LLLT) devices are FDA cleared for use in treating female pattern hair loss. As in men, hair transplant surgery is a safe and effective option, with more permanent and dramatic results.
There are various causes of temporary baldness. Temporary hair thinning can be caused by a number of medical conditions, but temporary hair loss in men is commonly caused by hypothyroidism. When this condition is treated, the temporary hair thinning is typically reversed. It is important to see a physician to determine whether or not this is the underlying cause. Other potential causes for temporary baldness include general anesthetic, high fever, physical trauma, and chemotherapy. Temporary hair loss in women can be caused by inadequate iron intake due to heavy menstruation or following pregnancy. This type of hair loss can be reversed with the help of iron supplements and medical treatment.
High stress levels can also result in temporary baldness. Although this type of temporary hair loss is not fully understood, emotional and hormonal factors can result in an abnormally high amount of shedding. In general with temporary hair loss, these hairs regrow after 3-4 months.
In this group of diseases, an inflammatory destruction of hair follicle structures can lead to permanent hair loss. The main goals of treatment are aimed at reducing the underlying inflammation and resultant symptoms of itching, burning, tenderness, and hair loss.
Lichen planopilaris (LPP)
This is a type of primary cicatricial alopecia that presents with one or more round to oval shiny patches of hair loss over the mid-scalp, sides of scalp, or back of the head.
Patients may complain of itching, burning or tenderness. Scalp examination usually reveals perifollicular erythema (redness around the follicle) and/or hyperkeratosis (scaling) during the early stages. Later on the condition can burn out and patients may have few symptoms or scalp redness. Scalp biopsy is helpful in confirming the diagnosis. Scalp pathology reveals a lymphocytic infiltrate around the opening (infundibulum) of the hair follicles, as well as a loss (destruction) of sebaceous glands. There is no FDA-approved therapy for this condition.
Treatment options include topical and intralesional corticosteroids, doxycycline (used for its anti-inflammatory effects), hydroxychloroquine, methotrexate, mycophenolate mofetil, and oral 5-alpha reductase inhibitors (finasteride, dutasteride). There is some evidence that the diabetes medication pioglitazone may also be helpful.
Frontal Fibrosing Alopecia
This primary cicatricial alopecia that presents with loss of hair along the frontal hairline.
Many patients also notice loss of eyebrows, sideburns, arm hair, and leg hair. Few patients complain of itching or tenderness, however, upon close inspection of the hairline, there may be a faint erythema (redness) as well as hyperkeratosis (scaling). The scalp pathology report is quite similar to that seen in LPP, showing a lymphocytic infiltrate around the hair follicles. Again, no FDA approved therapy exists but first-line treatments include topical and intralesional corticosteroids, doxycycline (used for its anti-inflammatory effects), hydroxychloroquine, methotrexate, mycophenolate mofetil, and oral 5-alpha reductase inhibitors (finasteride, dutasteride). There is some evidence that the diabetes medication pioglitazone may be helpful.
Central Centrifugal Cicatricial Alopecia (CCCA)
This type of hair loss is seen almost exclusively in patients of African descent, and most commonly in women.
It presents as a gradually increasing circle or oval of hair loss in the vertex (crown) of the scalp. Patients may also complain of itching, burning, or tenderness in the affected areas. There is evidence that this condition can run in families and is less likely to be due to grooming techniques such as relaxers or hot combs.
For early cases, a scalp biopsy is helpful in establishing the diagnosis and in order to start therapy to prevent disease progression. Pathology usually demonstrates a lymphocytic infiltrate with fibrosis and loss of sebaceous glands. There is also premature desquamation of the inner root sheath. Common therapies used are topical corticosteroids, oral doxycycline (for its anti-inflammatory role) and intralesional corticosteroid injections.
This form of cicatricial hair loss is seen more frequently in young men but women may also be affected.
Patients develop tender, crusted sores on the scalp that can evolve into shiny round or oval patches of hair loss with tufting (forced grouping) of nearby follicles. There may also be secondary infection with bacteria (Staphylococcus or Streptococcus) or fungi. Cultures are recommended in addition to a scalp biopsy to make the diagnosis. Unlike FFA or LPP, the scalp biopsy is characterized by a neutrophilic infiltrate. Treatment ideally involves clearing whatever infection exists, topical or intralesional corticosteroids, as well as anti-neutrophilic medications such as dapsone. Combination rifampin and clindamycin has also been used with success.
This type of hair loss presents almost exclusively in young men of African descent.
The condition begins with fluctuant, boggy patches over the scalp, and can evolve into confluent sinus tracts containing sterile pus. Scalp pathology shows a neutrophilic infiltrate, and bacterial or fungal cultures are usually negative. This is usually treated with oral antibiotics such as doxycycline or sulfamethoxazole/trimethoprim. The condition can be quite difficult to treat but newer biologic medications such as adalimumab have been shown to help.
Discoid Lupus Erythematosus (DLE)
Also known as chronic cutaneous lupus, this condition is a scarring autoimmune process that is limited to the skin and hair. It most commonly affects patients of African descent but may also be seen in Caucasians. Classically, it presents as one-to-many red scaly plaques on sun-exposed areas such as the scalp, ears and face (Figure 8).
Over time, these plaques will heal with depressed scarring and pigmentary changes. Follicular plugging with hair loss can occur, and scalp pathology shows a very brisk lymphocytic infiltrate that affects both skin and hair structures.
Only 5% of patients go on to develop systemic lupus. Those affected are also at an increased risk of developing certain skin cancers, namely squamous cell carcinoma, in chronic scars. Treatment aims to decrease inflammation and subsequent scarring. In addition to sun avoidance and protection, mainstay treatments include topical or intralesional steroids and hydroxychloroquine.
Folliculitis Acne Keloidalis
This condition is seen mostly in young men of African descent. It begins in the nape of the neck with small itchy bumps that resemble keloid scars. The scars can enlarge and become confluent and cover large areas of the back of the scalp.
Trauma from haircutting has been implicated as contributory, however it is still considered a primary cicatricial alopecia. Treatments include topical and intralesional corticosteroids, topical retinoids, and surgical excision when and if the areas become large or unsightly.
Erosive Pustular Dermatosis
This condition is less well understood but seems to occur as a result of chemical or mechanical trauma in areas of sun-damaged skin.
Patients with history of skin cancer surgery (Mohs), radiation, or chemotherapy with 5-fluorouracil or imiquimod have been reported in the literature. Scalp pathology demonstrates a mixed inflammatory infiltrate often with secondary bacterial colonization. The condition usually improves with high potency topical steroids such as clobetasol and clearance of any infection.
Secondary Cicatricial (Scarring) Alopecias
- Traumatic Causes – Permanent hair loss can result due to trauma from motor vehicle accidents, brain or scalp surgery, burns, cosmetic surgery such as face or brow lifts, or even prior hair surgery. In most cases they are amenable to hair transplantation although each patient should be carefully evaluated prior to surgery.
- Infection – Infection may rarely contribute to permanent hair loss, if it is long-standing in patients prone to keloid (scar) formation. One example might be with kerion formation (boggy tinea capitis).
This is defined as a diffuse hair shedding due to any major physiologically stressful event. The most common cause is childbirth, wherein women develop massive shedding 3-6 months after the baby is born. Other examples include high fever, crash dieting or rapid weight loss, general anesthesia, or prolonged illness or hospitalization. Hormonal or thyroid disorders may also contribute, as can nutritional deficiencies or certain medications. Telogen effluvium can also result from major life events such as death of a loved one, divorce, or financial loss.
Starting or stopping birth control can result in hair shedding. Many women suffer from polycystic ovarian syndrome (PCOS) or hyperandrogenism due to other causes (exogenous testosterone supplementation in post-menopausal women, or use of an androgenic progesterone in the setting of birth control). These forms of hair loss can often by addressed by ceasing the androgenic supplementation or by adding oral spironolactone, which is a diuretic with anti-androgen properties. Certain birth control pills containing drospirenone may also be helpful.
Patients with untreated hyper- or hypothyroidism may present with hair shedding. They may also notice eyebrow thinning or eyebrow loss.
Low levels of iron, zinc, and vitamin D have all been linked with hair shedding in the medical literature.
High dose vitamin A, isotretinoin, and certain cardiovascular drugs such as beta-blockers (metoprolol, propranolol) and low molecular weight heparin (and less commonly warfarin) have been linked with hair shedding. There is some evidence that the same patients who develop hair loss are also genetically predisposed to cardiovascular disease, in which case the drugs may have more of a confounding than a causative effect. In order to conclude that a medication is responsible for hair loss, a person must stop the drug, allow 3-6 months off it to see if the shedding resolves, and then (if they are willing) restart the drug to see if the shedding recurs. This process can take 6-12 months to fully evaluate. Patients should consult with their doctor before stopping any medication to avoid potentially dangerous effects.
This type of hair loss occurs due to a disruption of the hair growth cycle while it is in its actively growing (anagen) phase. It most frequently occurs after certain forms of chemotherapy. The hair loss begins in a matter of 2-4 weeks after beginning therapy. In most cases the hair loss is temporary but for others the hair may regrow only scantily or with permanently changed texture or caliber. Certain chemotherapy drugs such as busulphan and cyclophosphamide have been associated with permanent hair loss. Concurrent use of topical minoxidil has been shown to delay the loss of hair and speed its regrowth afterward.
This is an autoimmune form of hair loss that presents with small round-to-oval patches on the scalp but can affect larger, more confluent areas, as well as the eyebrows, eyelashes, and body hair. It most frequently presents in childhood but can occur at all ages. The hair follicles lose their usual immune privilege and come under attack by lymphocytes (T-cells). There may also be targeting of the melanocytes (pigment cells) associated with the follicles, resulting in white regrowth (poliosis). Alopecia totalis is loss of the entire scalp hair, while patients who lose of all body hair too develop alopecia universalis. Ophiasis is the term used to describe hair loss in the occipital scalp, and can be very difficult to treat. First-line therapies include topical and intralesional corticosteroids but more severe or longstanding cases can require systemic even immunosuppressive therapy such as methotrexate or prednisone. There is increased use in treatment of alopecia areata with JAK inhibitors. However, many cases resolve spontaneously with no treatment whatsoever. https://www.naaf.org
Congenital Triangular Alopecia
Also known as temporal triangular alopecia, this form of alopecia is localized to the frontotemporal scalp. It typically arises in early childhood and may present in a variety of shapes along the frontal and lateral hairlines including triangular, lancet-shaped or ovoid. There is no inflammation or scarring in this condition. On scalp pathology, the number of hair follicles is normal but many are miniaturized. The mainstay of therapy for adults is hair restoration surgery.
This condition results from a compulsive scratching or pulling at the hair. Because it is behavioral in cause, it is considered a psychiatric diagnosis, and falls under realm of obsessive-compulsive disease. It usually presents in childhood or adolescence, and can persist into adulthood. It is very difficult to treat without the help of a counselor and/or psychiatric medications. There is some evidence that N-acetylcysteine, which interacts with the GABA receptor may help address this condition.
This type of hair loss presents with breakage and thinning along the frontal hairline and sides, most often seen in women of African descent. It can occur due to tight braids, sewn or glued-in weaves, or wigs, but can occur in any setting where the hair is pulled very tightly such as gymnasts or Sikh men who grow hair very long. It can improve with topical minoxidil as well as hair transplantation.
This can occur in cases of prolonged bedrest or in babies who spend a lot of time resting on their back. It may also occur in patients who have undergone lengthy surgical procedures, exposing one side of their scalp to prolonged contact with the operating table. Typically, patients will notice a sharply demarcated circular patch of almost complete hair loss a few weeks after pressure has been applied. Most experience complete regrowth.
Radiation induced Alopecia
This hair loss can result from radiation treatments to the scalp and may result in permanent hair loss. It is usually amenable to hair restoration surgery.
This refers to a simple breakage of the hair shaft. It is either acquired from overly aggressive grooming techniques (flat irons, highlights, or relaxers) or inherited as a congenital defect (Arginosuccinic Aciduria, Citrullinemia, Menkes’ Syndrome). The presentation can mimic telogen effluvium because of the volume of hair found on the pillow, floor, or shower. Microscopic exam gives the appearance of “broomsticks stuck together” end-to-end. While there is no definitive cure, treatment is aimed at minimizing damage to the hair shaft and includes avoidance of chemicals and heating tools.
This condition is also known as bamboo hair, and is characterized by ball-and-socket abnormalities of the hair shaft. It is a rare condition, occurring in Netherton’s Syndrome in association with icthyosis linearis cirumflexa. It is also associated with atopy. It usually presents in infancy with short, sparse hair on the scalp, but also frequently affects the eyebrows.
This is also known as necklace hair, in which the hair has a beaded appearance. It is inherited in an autosomal dominant manner and results in short, broken hairs usually in early childhood, but it may also begin after puberty
This is a rare disorder where the hair shaft is flattened with twisting on its axis. Affected hairs are typically brittle and prone to breakage. It can occur alone or in the context of Menkes’ Syndrome.
This condition is also known as pili trianguli et canaliculi or uncombable hair. Patients have dry, stiff silver-blonde hair that sticks straight out from the scalp and has the appearance of spun glass. It presents in childhood and usually resolves by the teenage years.
Loose Anagen Syndrome
This condition is seen most often in female children with short blonde hair that seldom needs cutting. There is diffuse or patchy hair loss and parents may notice constant shedding. Microscopic examination shows a ruffled proximal cuticle. There are no underlying associated abnormalities and children are usually otherwise healthy. Most cases will improve spontaneously by adulthood.
Short Anagen Syndrome
As the name describes, the condition presents with a shortened hair growth cycle, such that the hairs do not achieve their full length and seldom require cutting. It is congenital but there are familial case reports suggesting an autosomal dominant inheritance pattern. It is usually diagnosed in young children aged 2-4.
This condition is caused by the sexual transmission of bacteria (Treponema Pallidum). Known as the “Great Mimicker” because of its ability to look like many other dermatologic conditions, syphilis can manifest as a few different forms of hair loss. Classically, it is associated with a patchy, “moth-eaten” alopecia, however it may also present with diffuse shedding, similar to telogen effluvium. Microscopically, there is usually an inflammatory infiltrate with lymphocytes and plasma cells. Treatment consists of a single dose of intramuscular penicillin.
This condition is caused by a fungal infection of the scalp, which most commonly occurs in children. Most cases can be traced back to a few different fungal organisms, known as dermatophytes, which can affect the skin, hair and nails. Significant itching is one of the most common complaints and patients typically experience scaling of the scalp that may be associated with broken hairs (“black dot” appearance) and possible alopecia. Because it is so common in children, tinea capitis should be suspected in any case of childhood hair loss. Diagnosis is usually confirmed with a fungal culture, which may take several weeks to grow. Definitive treatment is with oral antifungal medicines such as terbinafine or griseofulvin.
Aplasia cutis congenital of scalp
This is an isolated congenital defect in the skin, most commonly on the scalp. It presents at birth as an oval-shaped erosion, ulceration or depressed scar. A “hair collar sign,” which is a rim of long dark hairs around the periphery of the defect, may also be present. Though most cases are isolated and patients are otherwise healthy, some instances may be associated with an underlying skeletal abnormality or a genetic disorder (Bart Syndrome, Focal Dermal Hypoplasia), in which cases imaging studies may be performed. The only treatment required is wound care until the area completely heals.
This type of hair loss occurs due to certain forms of chemotherapy. The hair loss begins in a matter of 2-4 weeks after beginning therapy. Unlike telogen effluvium, there is no delay of 3-6 months. In most cases the hair loss is temporary but for others the hair may regrow only scantily or with permanently changed texture or caliber. The chemotherapeutic agent, Busulfan, has been associated with permanent hair loss. Use of Minoxidil has been shown to decrease duration of hair loss, though it cannot prevent it from occurring. It is not recommended in patients undergoing chemotherapy for hematologic malignancies.
There are several scalp conditions that can cause an itchy scalp, hair loss, and flaking; most can be treated with topical scalp meds. Among the most common is dandruff, which causes dead skin cells to flake and fall from the scalp onto the shoulders. Although it is a nuisance and is unattractive, this condition is primarily cosmetic; it does not result in a dry scalp, hair loss, or other serious consequences, and can generally be treated using dandruff shampoos that contain ketoconazole, zinc pyrithione tar or selenium oxide.
Other common conditions include excessive oiliness (seborrhea), and oily crusts adhering to inflamed, itchy, moist scalp skin (seborrheic dermatitis, also known as cradle cap in infants). The latter condition tends to be the most severe and should be treated by a dermatologist or other physician. However, an itchy scalp and hair loss rarely go hand-in-hand. However, regular scratching of the scalp can lead to hair breakage.
|Psychotropic Agents |
– Sodium Valproate
– SSRIs (Fluoxetine)
– LMW heparins
– Beta Blockers (Metoprolol, Propranolol)
– ACE Inhibitors (Captopril)
Cessation of Oral Contraceptives
– Vitamin A supplements
– Antiretrovirals (Indinavir)
– Alkylating Agents (cyclophosphamide)
– Anthracyclines (daunorubicin, idarubicin)
– Taxanes (paclitaxel, docetaxel)
– Vinca alkaloids (vinblastine, vincristine)
– Topoisomerase-1 inhibitors (topotecan, irinotecan)
– Actinomycin D
|Androgenetic Alopecia (AGA)|
|Androgenic Agents: May accentuate AGA|
– Anabolic Steroids
– Levonorgestrel (Mirena,
List of medications taken from:
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Mubki T, Rudnicka L, Olszewska M, Shapiro J. Evaluation and diagnosis of the hair loss patient: part I. History and clinical examination. J Am Acad Dermatol. 2014;71(3):415.e1-415.e15.
Mubki T, Rudnicka L, Olszewska M, Shapiro J. Evaluation and diagnosis of the hair loss patient: part II. Trichoscopic and laboratory evaluations. J Am Acad Dermatol. 2014;71(3):431.e1-431.e11.
James WD, Elston DM, Berger TG and Andrews GC. (2016). Andrews’ Diseases of the skin: clinical dermatology, 12th Edition. [London], Saunders/ Elsevier.
North American Hair Research Society: www.nahrs.org
Cicatricial Alopecia Research Foundation: www.carfintl.org