Hair Loss & Hair Transplant Glossary

This hair loss and hair transplant glossary is intended to help the non-medical individual navigate this website and to get a grasp on the many medical terms that are used by Dr. Lam, his staff, and throughout this website. The definitions herein are not meant to be exhaustively scientific in nature but are written in a more casual manner to offer an easy explanation on these terms and to serve as a ready reference as well.

Alopecia – This is simply a fancy medical term for “hair loss”. It is a term that describes any kind of hair loss, whether normal male pattern, female pattern, scarring, or otherwise (See Male-Pattern Hair Loss, Female Pattern Hair Loss, and Scarring Hair Loss). Many people use this term incorrectly to describe “alopecia areata” which is a particular type of alopecia. (See Alopecia Areata.)

Alopecia Areata – This type of hair loss usually manifests as circular patches in the scalp but can develop into a more global hair loss that can involve the entire scalp, eyebrows, and body hair. Although it is unclear what causes this type of hair loss, it is assumed to be partly immune-mediated in nature. It should not be corrected with hair transplant surgery but instead by steroid injections and other methods performed usually by a dermatologist.

Androgenetic Alopecia – This is a fancy medical term for male-pattern baldness. (See Male-Pattern Baldness.) It can also be used to describe women who lose hair in a male distribution, e.g., in the frontal corners of the hairline, etc.

Avodart – This is the brand name for Dutasteride. (See Dutasteride.)

Bulge – This describes the middle portion of the hair shaft that contains the highest portion of stem cells and permits hair regeneration and growth. It is vital that the assistant not damage this area during graft dissection or graft placement.

Central Forelock – This describes a subregion of the scalp that is situated in the midline immediately behind the hairline. It is of utmost importance to transplant sufficient hair density in the central forelock in order to create the appearance of a non-balding scalp with aesthetic benefit to the patient.

CCCA – This stands for Central Centrifugal Cicatricial Alopecia. It is a type of scarring hair loss that occurs primarily in individuals of African descent mainly in the crown or back of the head. (See Scarring Hair Loss.)

Dermal Papilla – The bottom part of the hair shaft that has significant regenerative capacity for the hair follicle. Accordingly, it should be kept intact during a hair transplant and should not be damaged during graft dissection or graft placement.

DHT – This stands for DiHydroTestosterone. The conversion of Testosterone to DHT can lead to male-pattern baldness in hairs that are sensitive to DHT, typically in the front, top, and crown of the scalp.

Di-Follicular Unit Graft (DFU) – A DFU is a graft that consists of two closely spaced follicular units (See Follicular Unit) that may improve visual density in the right candidate and still avoid unnaturalness. An ideal candidate is someone who has very closely spaced follicular units and perhaps has white hair. White hair looks very natural with DFU grafts, and dissecting DFUs minimizes the risk of transection (See Transection).

Donor Area – This describes the area in the back of the head where hair grafts are harvested for transplantation. The area that can be safely harvested without major risk for future hair loss is known as the safe donor area. (See Safe Donor Area.) The reason this area can be harvested for transplantation is based on the principle of donor dominance. (See Donor Dominance).

Donor Dominance – This principle was discovered in the 1950s that hairs taken from the back of the head where hairs are not predisposed toward hair loss (even in cases of advanced hair loss) still do not become susceptible to hair loss even when moved to the front of the head, an area prone to potential hair loss. It is the principle upon which modern hair transplanted is founded.

DUPA – Usually pronounced “Doopa”, this stands for diffuse unpatterned alopecia. DUPA describes miniaturization (See Miniaturization) that affects not only areas typically sensitive to DHT (See DHT) like the frontal and crown regions but also involves the donor area. With miniaturization of the donor area (See Donor Area), this would be a reason not to perform a hair transplant since transplanted hairs may be lost over time. A usual definition of DUPA is any degree of miniaturization in the donor area that exceeds 15 to 20%.

Dutasteride – This oral medication can be used off label in significant cases of male-pattern baldness. It blocks both type 1 and type 2 alpha-reductase, meaning that it has almost complete blockade of DHT (See DHT), the cause of male-pattern baldness (See Male-Pattern Baldness). It has a much longer half-life than finasteride (See Finasteride) and also a higher side-effect profile.

Female-Pattern Baldness – This describes the genetic predisposition of women to lose hair and is usually caused by hormonal influences. There are three main patterns of female-pattern hair loss: a Christmas tree pattern, a generalized loss known as Ludwig (See Ludwig), and a male-pattern baldness.

Finasteride – This is an oral medication, and now there is topical finasteride available taken by men (and in some cases post-menopausal women) to slow down androgenetic alopecia (See Androgenetic Alopecia). The medication works by blocking the conversion of testosterone to dihydrotestosterone (DHT) (See DHT) through inhibition of the 5-alpha reductase type 2 enzyme. It typically blocks about 60 to 70% of DHT. See Dutasteride.

Follicle – This is the name of the hair shaft and its accompanying structures including the muscle that attaches it to the surrounding tissue (known as the arrector pili muscle), sebaceous gland (oil gland), and related adnexa (the surrounding tissues around the hair shaft).

Follicular Unit – Hairs on the scalp grow not as individual single hairs but as clusters of hair groupings known as follicular units. These natural groupings of hairs in the scalp are composed of a bundle of 1-, 2-, 3-, and occasionally 4- and 5-hair clusters. These discrete clusters of hair follicles are typically what are divided into individual grafts known as follicular-unit grafts. These grafts are what are transplanted during a case whether performed via FUE (See FUE) or FUT (See FUT) procedure.

Front Fibrosing Alopecia (FFA) – This type of scarring alopecia, or scarring hair loss (See Scarring Hair Loss), that was first discovered in the early 1990s. It affects the frontal scalp and is evidenced by hair loss in the eyebrows and hairline oftentimes with thinning of the skin, skin papules (raised areas), and blood vessels observed. Like other types of scarring hair losses, it cannot be easily transplanted, as most of the grafts can fail. Unfortunately, the incidence of this type of hair loss is on the rise and can be easily confused with a patterned hair loss.

FUE – This stands for Follicular Unit Excision. The main advantage of FUE is that it is a technique used primarily for men who want to keep a closely worn haircut so as to avoid the possible visibility of a linear scar in the back of the head. Its main disadvantage is that you must shave your head to undergo this procedure. Further, it is not as ideal a technique for someone who has significant global hair loss due to over depletion of the valuable donor area. Individual follicular units (FUs) are harvested one at a time with a round punch either through robotic technique, by hand, or combination, depending on one’s anatomy and individual requirements.

FUT – This stands for Follicular Unit Transplant. FUT describes the technique of harvesting hairs from the back of the head using a linear incision. Many people believe that FUT is an outdated technique but it truly is not. Scars today can be imperceptible unless the hair is closely shaved. The main advantage of this technique is that it permits maximal hair harvesting for global, extensive hair loss; and no hair shaving preoperatively is required. In addition, hairs are harvested well within the safe donor area (SDA, See Safe Donor Area), which is harder to accomplish with large-session FUE harvests that can extend to the edge of the SDA. The main disadvantage of this procedure is that you may be unable to wear your hair very short without showing a linear scar.

Graft – A graft is typically comprised of a single follicular unit (See Follicular Unit) and is what is individually placed into the recipient sites (See Recipient Sites) during a hair transplant procedure.

Hair Cloning – This term is actually incorrect, as hairs are not in fact cloned. Further, no hair cloning has been achieved as of yet. In the future, it is with great hope that hairs from the donor area (See Donor Area) can be infinitely replicated using advanced techniques to permit an unlimited supply of transplantable hair. At this time, this is not possible.

Hair Curl – Each hair as it exits the scalp has a natural curl toward the scalp. When placing grafts, it is vital that the assistant place the grafts with the hair curl facing toward the scalp in order to ensure a natural and combable result. If the hair is clipped very short as in during FUE (See FUE), the skin cap is angled in a direction that will reveal the hair curl even when the assistant cannot see the actual hair curl itself.

Hair System – This is a modern term to describe a hairpiece usually for men. They have become far more natural today using actual human hair that is woven through a laced mesh to appear as hairs emanating naturally from the scalp. A cap describes a hair system that extends all the way down the sides of the head compared with a standard hair system that is attached to the existing hair through the use of clips or adhesive. A wig would be the female analogue to a cap. Hair transplants can be used to transition someone out of a hair system. Alternatively, hair transplants can be used to reduce the size of a hair system. For example, a hair transplant can be performed in the front and a hair system worn in the back. Finally, a hair transplant can be performed in the temples to match the hairline of the hair system since a hair system has a hard time achieving a natural temple appearance.

Lateral Hump – This describes a subregion of the scalp that lies on the sides of the head, i.e., on the vertical plane of the scalp, that must be recreated in cases of advanced baldness.

Ludwig – This is a scale for female hair loss divided into 3 grades. Grade 1 is early diffuse loss. Grade 2 is moderate diffuse hair loss. Grade 3 reflects significant diffuse hair loss.

Male-Pattern Baldness – Also known as androgenetic alopecia (See Androgenetic Alopecia), this type of hair loss is caused by hair follicles that are sensitive to the effects of DHT (See DHT) usually in the frontal, central, and crown regions of the head and that are consequently lost over time.

Midscalp – This describes the subregion of the scalp that lies between the central forelock anteriorly and ends posteriorly at the vertex transition zone (See Central Forelock and Vertex Transition Zone).

Miniaturization – Patterned hair loss (See Female-Pattern Hair Loss and Male-Pattern Hair Loss) occurs through a process in which thick, terminal hairs (See Terminal Hairs) gradually become thinner, wispier, and more transparent known as miniaturized, or vellus hairs (See Vellus Hairs), that eventually are lost to complete baldness.

Minoxidil – This topical medication that can be used for both men and women can reverse, slow down, but cannot entirely stop the balding process in male- and female-pattern hair loss. The trade name in the United States is Rogaine and in Europe it is marketed as Regaine. The mechanism by which hair loss is reversed is unclear but it can start to take effect as early as 4 to 6 weeks. It is sold over the counter, and it can with the help of finasteride (See Finasteride) act synergistically to improve male hair loss. It comes in 2% and 5% dosages with the 2% used for women, and the 5% used for both men and women. There are specialized compounded versions of minoxidil that can enhance efficacy.

Norwood Classification – This classification system developed by O’Tar Norwood breaks down the progression of male hair loss into 7 stages. It is important way for surgeons to document the degree of hair loss, and it also can serve as a template by which a surgeon designs a hair pattern that mimics nature.

Plugs – Although people still use this term to refer to hair transplant today, this term is entirely outdated. Old plugs described 4-mm round punch grafts containing 16 to 20 hairs (today grafts contain 1 to 4 hairs) that were removed from the donor area (See Donor Area) and transplanted without further dissection. These grafts appeared entirely unnatural and are no longer used. In the 1980s, these plugs were divided into minigrafts and micrografts in which they were indiscriminately cut up into quarter and half sizes. Today, the technique involves transplanting only single follicular units as grafts (See Follicular Unit).

Propecia – This is the trade name for 1 mg oral finasteride used for male-pattern baldness (See Finasteride).

Rogaine – This is the trade name used in the United States for minoxidil (See Minoxidil).

Recipient Dominance – When hairs are transplanted to the recipient area, the grafts typically preserve the donor characteristics from where they came (See Donor Dominance). However, at times, the recipient area may influence how the grafts grow after transplantation. For example, transplanted eyebrow hairs from the scalp may start to slow down their growth after 1 to 2 years to resemble the pattern of natural eyebrow hairs.

Recipient Sites – These are small slits made by specialized blades or needles into which the grafts (See Grafts) are placed.

Safe Donor Area (SDA) – The safe donor area describes the region of the donor area (See Donor Area) in the back and sides of the head that are considered safe to be used as a graft source since it is proposed that hair will not be lost in the future in this area due to donor dominance (See Donor Dominance). For someone with progressive hair loss, the SDA may become increasingly smaller over time.

Scarring Alopecia – Same as Scarring Hair Loss (See Scarring Hair Loss).

Scarring Hair Loss – Also known as Scarring Alopecia, this is an active skin disease that shows scarring within the skin that can prevent or limit the success of a hair transplant. If not properly diagnosed, a hair transplant result may be unsuccessful (See CCCA and Frontal-Fibrosing Alopecia).

Shock Loss – This condition describes the hair shedding that may occur in the weeks to months following a hair transplant procedure due to the trauma of the procedure or the use of epinephrine. This is more common in women but can be minimized (but not entirely avoided) by using medications like minoxidil (See Minoxidil) for a minimum of 4 to 6 weeks prior to the procedure. See Telogen Effluvium.

Slivering – After a donor strip of tissue is removed during an FUT procedure (See FUT), the strip is then “breadloafed” into a single sheet layer of hair follicles. This process of breadloafing the strip is known as slivering. These slivers are then further dissected into individual grafts consisting of individual follicular units (See Follicular Unit).

SMP (Scalp Micropigmentation) – SMP refers to temporary or permanent tattooing of the scalp in which the tiny tattoo marks simulate hair follicles. SMP can be used to minimize donor scars or to add further visual hair density to an individual with or without hair transplant surgery. This procedure requires both technical and artistic skill to implement.

Telogen Effluvium – This type of hair loss is usually self-limiting but can be chronic in nature that leads to a lot of hair shedding but rarely frank baldness. It occurs when hairs shift from the anagen growth phase to the telogen phase in which the hairs fall out. It usually follows by several weeks to a couple of months an event like surgery, general anesthesia, pregnancy, protein-malnourished weight loss, general sickness. Shock loss (See Shock Loss) that follows a hair transplant surgery is caused most commonly by telegon effluvium.

Temporal Point – The triangular point of hair in the temporal region of the scalp that can be reconstructed to provide a better total frame to the frontal hairline.

Terminal Hairs – These are the same thick hairs one possesses before the onset of patterned hair loss (See Female-Pattern Hair Loss and Male-Pattern Hair Loss). These terminal hairs gradually undergo a process of miniaturization (See Miniaturization) in which they become vellus hairs (See Vellus Hairs) and can eventually be entirely lost leading to frank baldness.

Traction Alopecia – This type of non-scarring hair loss is caused by mechanical pulling on the hair long enough that the hair dies. This is most classically seen in the temples in African-American women who braid or pull their hairs tightly. It can also be seen in Sikh men who wear their hairs tightly turned into a knot under a turban. With adequate donor hair to cover the loss, this condition is very treatable with hair transplant surgery.

Transection – This describes the inadvertent cutting through of a hair shaft usually during harvesting of hairs during a hair transplant procedure whether via the FUE (See FUE) or the FUT (See FUT) method. Transected hairs typically have a lower chance of survival, especially if the dermal papilla (See Dermal Papilla) or the bulge (See Bulge) regions are lost.

Trichophytic Closure – This type of wound closure following FUT (See FUT) donor harvesting involves removing 1 mm of epidermis (outer skin) along the bottom wound edge, which allows for hair from this denuded line to grow through the scar to make it much harder to see.

Trichotillomania – This psychological condition is a type of obsessive-compulsive disorder (OCD) in which an individual compulsively pulls one’s own hair out. If the condition is stable and well treated by a psychiatrist with appropriate medications, hair transplant surgery could be an option.

Vellus Hairs – These hairs are the tiny, wispy, transparent hairs, which are also known as miniaturized hairs, that are observed in the intermediate phase of a patterned hair loss (See Female-Pattern Hair Loss and Male-Pattern Hair Loss). Terminal hairs (See Terminal Hairs) become vellus hairs, which then over time can be entirely lost leading to partial or complete baldness.

Vertex – This is another name for the crown of the head. The crown describes the posterior part of the head that falls on the vertical plane of the scalp, and a crown transplant can be undertaken in the appropriate candidate.

Vertex Transition Zone (Point) – This describes the semilunar (arced) line between the midscalp and the crown of the head, i.e., the transition from the horizontal to the posterior plane of the scalp. This can mark the anterior limit of a crown hair transplant or the posterior limit of a frontal hair transplant.

Whorl – This describes the circular direction of hairs that are usually present in the crown but may also be observed in certain hairlines like female hairlines or in other regions of the scalp.