Hair Loss and Hair Transplant Glossary
Understanding terminology can sometimes feel overwhelming. From medical terms like androgenetic alopecia and follicular miniaturization to surgical terminology such as grafts and follicular units, patients are often introduced to unfamiliar language during their research. At De Haar, we believe that understanding your diagnosis and options begins with understanding the terminology. This glossary explains many of the most common words and phrases used in hair transplantation field in clear, patient-friendly language, helping you feel more informed and confident throughout your hair restoration journey.
A
Alopecia: The medical term for hair loss. Alopecia describes any condition that results in partial or complete hair loss and includes many different types, such as androgenetic alopecia, alopecia areata, telogen effluvium, and scarring alopecia.
Alopecia Areata: An autoimmune condition in which the immune system mistakenly attacks healthy hair follicles, resulting in smooth, round patches of hair loss. Hair regrowth is often possible because the follicles usually remain alive.
Anagen Phase: The active growth phase of the hair cycle. Approximately 85–90% of healthy scalp hairs are normally in the anagen phase at any given time. Depending on the individual, this phase can last between two and seven years.
Androgenetic Alopecia: The most common cause of hair loss in both men and women. Often referred to as male or female pattern hair loss, it occurs when genetically susceptible hair follicles gradually shrink under the influence of dihydrotestosterone (DHT).
Anisotrichosis: Anisotrichosis is the medical term for variation in hair shaft diameter. It is one of the hallmark findings seen during Trichoscopy in androgenetic alopecia and reflects the process of follicular miniaturization.
Arrector Pili Muscle: The arrector pili is a tiny muscle attached to each hair follicle. When stimulated by cold temperatures or emotion, it contracts, causing the hair to stand upright and producing what are commonly known as “goosebumps.”
Autoimmune Disease: An autoimmune disease occurs when the body’s immune system mistakenly attacks its own healthy tissues. Several autoimmune conditions can affect the hair and scalp, including alopecia areata, lupus erythematosus, lichen Planopilaris, frontal fibrosing alopecia, and psoriasis. Early diagnosis is often important to prevent ongoing inflammation and preserve healthy hair follicles.
Alopecia Totalis: A condition that results in no hair on the scalp.
Alopecia Universalis: A condition where there is no hair on any part of the body, this includes eyelashes, eyebrows, and scalp hair. It may develop as alopecia areata or result from another cause
Amino Acids: The building blocks of protein.
Amortization: The process of converting an enzyme.
Anagen Effluvium: Loss of hair that is supposed to be in the anagen or growing phase. This is hair loss that is generally associated with chemotherapy or radiation.
Androgen: Male hormones
B
Biopsy: A minor procedure in which a small sample of scalp tissue is removed and examined under a microscope. A biopsy is sometimes recommended when the diagnosis is unclear or when inflammatory or scarring hair disorders are suspected.
C
Catagen Phase: A short transitional stage of the hair growth cycle during which active hair growth stops, and the follicle begins preparing for its resting phase.
Central Centrifugal Cicatricial Alopecia (CCCA): Central Centrifugal Cicatricial Alopecia (CCCA) is a form of scarring hair loss that most commonly affects women of African descent. Hair loss typically begins at the crown of the scalp and gradually spreads outward. Because CCCA permanently damages hair follicles, early diagnosis and treatment are essential to slow progression and preserve remaining hair.
Congenital Triangular Alopecia: Congenital triangular alopecia is a rare, non-scarring condition that usually appears during early childhood. It is characterized by a stable, triangular or oval area of hair loss, most commonly affecting the front or temple region of the scalp. The condition is not progressive and is often mistaken for alopecia areata. Hair transplantation can be an excellent treatment option for suitable patients.
Crown: The area at the back and top of the scalp where hair often thins in people with androgenetic alopecia.
D
Dermal Papilla: The dermal papilla is a small structure located at the base of each hair follicle. It contains blood vessels that deliver oxygen and nutrients to the growing hair. Healthy communication between the dermal papilla and the follicle is essential for normal hair growth.
DHT (Dihydrotestosterone): A hormone derived from testosterone that plays a central role in androgenetic alopecia. In genetically susceptible individuals, DHT gradually causes hair follicles to shrink, producing progressively finer hairs over time.
Discoid Lupus Erythematosus (DLE): Discoid Lupus Erythematosus is a chronic autoimmune condition that primarily affects the skin and scalp. It can cause inflammation, scarring, changes in skin pigmentation, and permanent hair loss if left untreated. Early diagnosis is important to control inflammation and minimize irreversible damage to the hair follicles.
Donor Area: The region at the back and sides of the scalp where hair follicles are genetically resistant to DHT. These follicles are commonly used during hair transplantation because they usually retain their characteristics after transplantation.
Donor Density: Donor density refers to the number of healthy hair follicles available within the donor area. Assessing donor density is an important part of determining a patient’s suitability for hair transplantation and planning the number of grafts that can be safely harvested.
Donor Dominance: The principle that transplanted hair retains the genetic characteristics of the donor area after being moved to another part of the scalp.
E
Exogen: The shedding phase of the hair cycle during which mature hairs naturally fall out, allowing new hairs to emerge.
Ectodermal Dysplasia: Ectodermal dysplasia is a group of rare inherited genetic disorders that affect the development of structures derived from the ectoderm, including the hair, teeth, nails, sweat glands, and skin. People with ectodermal dysplasia often have sparse, fine, slow-growing, or absent scalp hair, as well as reduced eyebrows and eyelashes. The degree of hair involvement varies depending on the specific type of ectodermal dysplasia. Because the condition affects the development of the hair follicles themselves, treatment options differ from those used for more common forms of hair loss. A comprehensive assessment is important to determine the most appropriate management plan, which may include medical treatment, cosmetic solutions, or, in carefully selected cases, hair transplantation.
F
Follicle: The tiny structure within the skin that produces hair.
Follicular Miniaturization: The gradual shrinking of hair follicles seen in androgenetic alopecia. As follicles become smaller, they produce hairs that are finer, shorter, and less pigmented.
Follicular Unit: A naturally occurring group of one to four hairs that grow together from the scalp. Hair transplantation involves moving these naturally occurring follicular units.
Folliculitis Decalvans: Folliculitis Decalvans is a rare inflammatory scalp disorder in which chronic inflammation damages the hair follicles, leading to scarring hair loss. Symptoms may include redness, tenderness, pustules, crusting, and itching. Prompt diagnosis and treatment are important to reduce inflammation and help preserve unaffected hair follicles.
FUE (Follicular Unit Extraction): A hair transplant technique in which individual follicular units are carefully removed from the donor area and transplanted into thinning or bald areas.
FUT (Follicular Unit Transplantation): A hair transplant technique that involves removing a thin strip of scalp from the donor area. Individual follicular units are then dissected under a microscope before transplantation.
Frontal Fibrosing Alopecia (FFA): Frontal fibrosing alopecia is a form of scarring alopecia that most commonly affects postmenopausal women, although it can occur in men and younger women. It typically causes gradual recession of the frontal hairline and loss of the eyebrows. Early diagnosis is essential because treatment is aimed at slowing progression rather than restoring hair that has already been lost.
G
Graft: A follicular unit that has been harvested for transplantation. A single graft may contain one, two, three, or occasionally four hairs.
Graft Survival: Graft survival refers to the percentage of transplanted hair follicles that successfully establish a blood supply and continue to grow after surgery. Modern techniques and meticulous handling of grafts help maximize survival rates.
Graft Yield: Graft yield describes the number of healthy follicular units successfully harvested during a hair transplant procedure while preserving the integrity of the donor area.
H
Hair Density: The number of hairs growing within a given area of the scalp.
Hairline: The hairline is the natural border between the forehead and the hair-bearing scalp. Its shape, position, and density play an important role in facial appearance and are carefully considered during hair transplant planning.
Hairline Design: The process of planning the position, shape, density, and contour of the hairline to achieve the most natural-looking result possible.
Hair Bulb: The hair bulb is the enlarged base of the hair follicle located beneath the skin. It contains actively dividing cells responsible for producing the hair shaft and surrounds the dermal papilla, which supplies nutrients necessary for healthy hair growth.
Hair Calibre: Hair calibre describes the thickness of an individual hair strand. People with thicker hair calibre often achieve greater visual density than those with naturally fine hair, even when the number of hairs is the same.
Hair Diameter: Hair diameter is the measurement of the thickness of an individual hair shaft. One of the earliest signs of androgenetic alopecia is a gradual reduction in hair diameter caused by follicular miniaturization.
Hair Pull Test: The hair pull test is a simple clinical examination used to assess active hair shedding. During the test, the clinician gently pulls a small group of hairs to determine whether an excessive number are released, which may indicate conditions such as telogen effluvium or active inflammatory hair loss.
Hair Shaft: The hair shaft is the visible portion of the hair that extends above the surface of the skin. It is composed primarily of keratin, a strong structural protein. In androgenetic alopecia, the hair shaft gradually becomes finer and shorter as the hair follicle undergoes miniaturization.
Hair Matrix: The hair matrix is a group of rapidly dividing cells located within the hair bulb. These cells produce the hair shaft and determine the thickness, colour, and rate of hair growth.
Hyperandrogenism: Hyperandrogenism refers to higher-than-normal levels of male hormones (androgens) in women. It may be associated with conditions such as Polycystic Ovary Syndrome (PCOS) and can contribute to female pattern hair loss, acne, and increased facial or body hair. Identifying and treating the underlying hormonal imbalance is an important part of managing hair loss.
Hypotrichosis: Hypotrichosis is a condition characterized by an abnormally low amount of hair growth. It may be present at birth (congenital) or develop later in life due to certain medical conditions. Depending on the cause, hypotrichosis can affect the scalp, eyebrows, eyelashes, or body hair. Treatment depends on the underlying condition and the health of the remaining hair follicles.
I
Iron Deficiency: Iron deficiency is a common medical cause of diffuse hair shedding, particularly in women. Low iron stores can interfere with the normal hair growth cycle and may contribute to telogen effluvium. Blood tests can help determine whether iron deficiency is contributing to hair loss.
L
Lupus (Systemic Lupus Erythematosus): Lupus is an autoimmune disease that can affect many parts of the body, including the skin and scalp. Some forms of lupus may cause temporary hair shedding, while others can lead to scarring hair loss if inflammation damages the hair follicles. Prompt diagnosis and medical management are important to help protect both overall health and hair growth.
Lichen Planopilaris (LPP): Lichen Planopilaris is an inflammatory autoimmune condition that affects the scalp and permanently damages hair follicles. It is a form of scarring alopecia and may cause itching, burning, redness, and progressive hair loss. Early treatment aims to control inflammation and preserve remaining hair.
Ludwig Scale: A commonly used classification system for female pattern hair loss.
M
Menopause: Menopause is a natural stage of life marked by a decline in estrogen levels. These hormonal changes can contribute to reduced hair density and female pattern hair loss in genetically susceptible women. Many women notice increased scalp visibility or a widening part during and after menopause. A thorough assessment can help determine the most appropriate treatment options.
Microneedling: A treatment that creates tiny, controlled microchannels in the skin to stimulate healing and may enhance hair growth when combined with appropriate therapies.
Mid-Scalp: The mid-scalp is the area located between the frontal hairline and the crown. It commonly becomes thinner as androgenetic alopecia progresses and may require treatment during hair restoration.
Minoxidil: A topical or oral medication used to help slow hair loss and stimulate hair growth in suitable patients.
N
Norwood Scale: The most widely used classification system for male pattern hair loss.
P
Platelet-Rich Plasma (PRP): A treatment that uses a concentrated portion of the patient’s own blood containing growth factors to support hair follicle function.
Polycystic Ovary Syndrome (PCOS): Polycystic Ovary Syndrome (PCOS) is a common hormonal condition that affects women of reproductive age. Elevated androgen (male hormone) levels associated with PCOS can contribute to female pattern hair loss, scalp thinning, excess facial or body hair, acne, and irregular menstrual cycles. While PCOS does not directly cause hair follicles to disappear, it can accelerate androgenetic alopecia in genetically susceptible women.
Protein Deficiency: Hair is primarily composed of a protein called keratin. Inadequate protein intake or conditions that affect protein absorption may disrupt the normal hair growth cycle and contribute to increased hair shedding. Maintaining a balanced diet with adequate protein is important for healthy hair growth.
Psoriasis: Psoriasis is a chronic autoimmune skin condition that causes thick, red, scaly patches on the skin and scalp. Scalp psoriasis itself does not usually cause permanent hair loss, but inflammation, scratching, and temporary disruption of the hair growth cycle can lead to increased shedding. Hair typically regrows once the inflammation is effectively treated.
R
Recipient Area: The recipient area is the part of the scalp where transplanted grafts are placed to restore hair density or reconstruct the hairline.
S
Safe Donor Zone: The safe donor zone is the region around the back and sides of the scalp where hair follicles are genetically resistant to the effects of DHT. These permanent follicles are used during hair transplantation because they generally continue to grow after being transplanted.
Sebaceous Gland: Sebaceous glands are attached to each hair follicle and produce sebum, the scalp’s natural oil. Sebum helps lubricate and protect both the scalp and hair. Disorders affecting these glands may contribute to certain scalp conditions but are not usually a direct cause of pattern hair loss.
Seborrheic Dermatitis: Seborrheic dermatitis is a common inflammatory scalp condition that causes redness, itching, and greasy yellow or white flakes. Although it does not directly cause permanent hair loss, ongoing inflammation and scratching may contribute to temporary hair shedding. Effective treatment often improves scalp health and allows normal hair growth to resume.
Scalp Biopsy: A scalp biopsy is a minor procedure in which a small sample of scalp tissue is removed and examined under a microscope. It may be recommended when the diagnosis is uncertain or when inflammatory or scarring hair disorders are suspected.
Scarring Alopecia: Scarring alopecia, also known as cicatricial alopecia, refers to a group of inflammatory disorders that permanently destroy hair follicles and replace them with scar tissue. Early diagnosis and treatment are essential because hair loss caused by scarring alopecia is often irreversible once follicles have been destroyed.
Shock Loss: Shock loss is a temporary shedding of existing hairs that can occur after a hair transplant or other scalp procedures. Although it can be concerning, the affected hairs often regrow over the following months as the follicles recover.
T
Telogen Phase: The resting stage of the hair cycle before a hair is naturally shed.
Telogen Effluvium: A temporary form of diffuse hair shedding that typically occurs two to four months after a physical or emotional stressor.
Terminal Hair: Terminal hairs are thick, fully developed, pigmented hairs that provide the density and coverage typically seen on a healthy scalp. The goal of most hair restoration treatments is to preserve or restore terminal hair growth.
Temporal Recession: Temporal recession refers to hair loss at the temples and is often one of the earliest signs of male pattern hair loss. Mild recession is a normal part of the maturation of the male hairline, while progressive recession may indicate androgenetic alopecia.
Thyroid Disease: Both an underactive thyroid (hypothyroidism) and an overactive thyroid (hyperthyroidism) can contribute to diffuse hair thinning and increased hair shedding. Because thyroid disorders are treatable, identifying and correcting the underlying hormonal imbalance often improves hair growth over time.
Trichoscopy: Trichoscopy is a non-invasive examination performed using specialized magnification to evaluate the scalp and hair follicles. It helps identify hair shaft miniaturization, variation in hair diameter, scalp inflammation, and many other features that assist in diagnosing different forms of hair loss.
V
Vellus Hair: Vellus hairs are fine, soft, lightly pigmented hairs that provide little cosmetic coverage. During androgenetic alopecia, terminal hairs gradually become miniaturized and begin to resemble vellus hairs.
Vertex: The vertex, also known as the crown, is the area at the back of the top of the scalp where hair naturally forms a spiral or whorl. It is one of the most common areas affected by male pattern hair loss and often requires a different graft placement strategy than the frontal hairline.
Vitamin D Deficiency: Vitamin D plays an important role in normal hair follicle function. Although research is ongoing, low vitamin D levels have been associated with several forms of hair loss. If a deficiency is identified, appropriate supplementation may be recommended as part of a comprehensive treatment plan.
W
Widow’s Peak: A widow’s peak is a naturally occurring V-shaped point in the centre of the hairline. It is a normal anatomical variation and may be preserved or recreated during hairline design when appropriate.
Z
Zinc Deficiency: Zinc is an essential mineral that supports normal hair follicle function and tissue repair. Zinc deficiency may contribute to increased hair shedding, brittle hair, and slower hair growth. Blood tests can help determine whether a deficiency is present, and treatment involves correcting the underlying nutritional imbalance.
