Table 2.

Variables and definitions used for examination of the scalp, eyebrow and eyelash hair.¹⁶

Variable	Definition	Additional remarks
Scalp hair colour
Black/dark brown
Brown
Sandy/blonde
Red
Scalp hair texture
Straight	Forms a straight line or “I” shape
Wavy	Forms a semi-circle, crescent or “S” shape
Curly	Forms a full circle, ring or “O” shape
Eyebrow density
Absent	No eyebrows present
Sparse	Decreased density/number and/or decreased diameter of eyebrow hairs	Can be regional (medial, lateral) or total
Eyebrow morphology
Broad	Regional increase in width of the eyebrow	Can be regional (medial, lateral) or total
Flared	Widening with a change in direction of the eyebrow hairs
Highly arched	Increased height of the central portion of the eyebrow forming a crescent, semi-circular or inverted U-shape
Horizontal	An eyebrow that extends straight across the brow without a curve
Synophrys	Meeting of the medial eyebrows in the midline
Eyebrow skin
Erythema	Redness of skin
Keratosis pilaris	Discrete follicular papules with scale
Eyelash density
Absent	No eyelashes are present
Sparse	Decreased density/number of eyelashes	Can be regional (medial, lateral, upper, lower) or total
Eyelash morphology
Trichomegaly	Increased length of the eyelashes
Prominent	Eyelashes that draw attention of the viewer due to increased density and/or length and/or curl without meeting the criteria of trichomegaly
Distichiasis	An extra row of eyelashes emerges from the ducts of meibomian glands
Trichiasis	Eyelashes curved inward toward the cornea
Scalp hair light microscopy
Hair diameter	Measured in mm
Pigmentation	Light (translucent) Medium/dark (near opaque/opaque)
Medullation	A dark line due to air spaces within the medulla in the center of the hair shaft	Can be continuous or discontinuous Independent of the degree of pigmentation but correlates with the hair diameter
Hair cycle	Anagen (pigmented triangular bulb or bent bulb) Catagen/telogen (depigmented club-shaped bulb, not bent)