UNIQUE BIOLOGIC FEATURES OF AFRO-TEXTURED HAIR

SHAPE:

  • Curved/ Curly  hair and follicle in the scalp |  Elliptical (Caucasians- oval  &Asians round)

  • A high degree of irregularity in the diameter along the hair shaft, with frequent twists and random reversals in direction with pronounced flattening. 

  • African hair tends to form knots

STRENGTH:

  • Lower stress required to break the hair

  • Earlier breaking time under a given force 

  • Microcracks and fractures in the hair fiber caused by natural constrictions along the twisted hair shaft leading to lower tensile strength and relative brittleness.  This is made worse by everyday combing and grooming

  • Least amount of cuticle layers leading to a higher prevalence of hair breakage

  • Fewer elastic fibers anchoring the hair follicles to the dermis in the black subjects, leading to an increased susceptibility to traction alopecia

SEBACEOUS (OIL) GLANDS:

  • Uneven distribution of sebum from root to tip resulting in  dryer hair

 

GROWTH RATE:

  • Slower

 

References: 

- Taylor SC.  Skin of color: biology, structure, function, and implications for dermatologic disease.  J Am Acad Dermatol. 2002 Feb;46(2 Suppl Understanding):S41-62. 

- Franbourg A, Hallegot P, Baltenneck F, Toutaina C, Leroy F. 2003 Current research on ethnic hair. J. Am. Acad. Dermatol. 48, S115–S119.

- Aguh C, Okoye G, eds. Fundamentals of Ethnic Hair: The Dermatologist's Perspective. Cham: Springer, 2016

- Cloete E, Khumalo NP, Ngoepe MN.  The what, why and how of curly hair: a review.  Proc Math Phys Eng Sci. 2019 Nov;475(2231):20190516