5-alpha reductase: enzyme produced in the prostate, adrenal glands and scalp skin that metabolizes the male hormone testosterone into Dihydrotestosterone (DHT).

alopecia areata: is a hair loss condition in which hair is lost from some or all areas of the scalp, and sometimes from the body. The alopecia most commonly develops as distinct spots of hair loss on the scalp.

androgen receptor gene: gene on the X chromosome that codes the synthesis of cell receptors specific for male sex hormones. Alterations are associated with an increased risk of androgenetic alopecia, however it remains unclear how changes in the androgen receptor gene increase the risk of patterned hair loss in men and women.

androgenetic alopecia: male-pattern baldness in men typically characterized by a receding hairline and hair thinning on the crown, and female-pattern baldness in women typically characterized by diffuse hair loss most noticeably at the part line and top area just behind the bangs, while often maintaining their front hairline. Related to the effects of androgens on hair growth.

aplasia cutis congenita: absence of a portion of scalp skin in a localized area at birth. Can cause a parchment-like scar with associated alopecia.

autologous: derived or transferred from the same individual’s body.

central centrifugal alopecia: a pattern of progressive, symmetric scarring alopecia on the vertex of the scalp. Encompasses hot comb alopecia, follicular degeneration syndrome, pseudopelade in African Americans and central elliptical pseudopelade in Caucasians.

cicatricial alopecia: rare disorder that destroys the hair follicle and replaces it with scar tissue, causing permanent hair loss.

collagen: major structural protein in the human body.  In tendons, collagen is arranged in bundles of parallel fibres giving them a rope-like appearance.

congenital alopecia: a rare inherited form of reduced or absent of scalp hair from infancy.

congenital hypotrichosis: genetic condition causing no hair growth or very limited hair growth from infancy.

congenital triangular alopecia: a condition causing non-scarring loss of hair mass on the scalp’s temporal regions and usually first observed in infancy.

dermal papilla (DP): a small pear-shaped extension of the hair follicle dermal mesenchyme into the epithelial tissue in the hair follicle bulb.

dermal sheath: the connective tissue sheath around the outer limits of the hair follicle.

dermal sheath cup cells: type of hair follicle cell located at the lower pole of the hair bulb in a position surrounding the hair bulb in a ‘cup-like’ manner. These cells have been found to retain regenerative and hair growth inducing capacities

dermatology: is the branch of medicine dealing with the skin and its diseases. A dermatologist takes care of diseases of the skin, scalp, hair, and nails.

dihydrotestosterone (DHT): androgen synthesized in the prostate gland, testes, hair follicles, and adrenal glands by the enzyme 5-alpha reductase. DHT is thought to be most responsible for the type of hair loss known as androgenetic alopecia (male pattern baldness and female pattern hair loss).

dissecting cellulitis: rare chronic scalp condition causing progressive scarring and degeneration of the scalp skin and hair follicles.

fascicles: a small or slender bundle.

fibrils: a fine fibre, such as a root hair or a thread of muscle tissue.

fibroblasts: the principal active cells of connective tissue.

fibrous: consisting of, containing, or resembling fibres.

folliculitis decalvans: scarring alopecia that leads to inflammation of involved parts of the scalp along with pustules, erosions, crusts, and scale.

frontal fibrosing alopecia: a condition in postmenopausal women characterized by progressive frontal hairline recession associated with scarring.

GCP (Good Clinical Practice): international quality standard provided by the International Conference on Harmonization (ICH), an international body that defines standards for clinical trials involving human subjects. GCP guidelines include protection of human rights as a subject in clinical trials and provide assurance of the safety and efficacy of newly developed compounds.

GMP (Good Manufacturing Practices) conditions: GMP are the part of quality assurance that ensures that drugs are consistently produced and controlled in such a way to meet the quality standards appropriate to their intended use, as required by the marketing authorization.

hypocellular: containing less than the normal number of cells.

immunology: is a broad branch of biomedical science that covers the study of all aspects of the immune system.

lichen planopilaris: affects the hair-producing areas of the body, causing inflammation, hair loss, and scarring.

microtear: minor damage to soft tissue.

morphogenesis: the biological process that causes an organism to develop its shape. It is one of three fundamental aspects of developmental biology along with the control of cell growth and cellular differentiation.

neovascularity: Proliferation of blood vessels in tissue not normally containing them.

plasma: is the liquid portion of blood that holds blood cells in whole blood in suspension.  It is made mostly of water and contains dissolved proteins, clotting factors, hormones, electrolytes, and carbon dioxide.

pseudopelade (of Brocq): a unique form of cicatricial (scarring) alopecia resembling localized patches of alopecia.

scarring alopecias: diverse group of rare disorders that destroy the hair follicle, replace it with scar tissue, and cause permanent hair loss. Also referred to as “cicatricial alopecia”.

telogen effluvium: form of nonscarring alopecia characterized by diffuse hair shedding, often with an slowly progressive onset.

tendinopathy: refers to a disease of a tendon (“-opathy” referring to a disease or disorder).

tenocytes: fibroblasts found in the tendon.

traction alopecia: form of alopecia, or gradual hair loss, caused primarily by pulling or force being applied to the hair.

tufted folliculitis: rare, progressive pattern of scarring alopecia that affects the scalp.