Mechanical Properties of Hairs from Patients with Different Types of Hair Diseases

The following mechanical properties of hair have been studied: tensile strength, strain at break, and elastic modulus. The determinations were made at constant temperature and humidity on fifty separate hairs from each patient. The mechanical properties of the fibrous material were similar for thick and thin hair. The elastic modulus and tensile strength showed a good correlation. Five patients with ectodermal dysplasia and one with congenital ichthyosiform erythrodermia had a lower elastic modulus than the other groups. Hair from those with ectodermal dysplasia also showed a low tensile strength. No significant difference in mechanical properties were found between normal-appearing hair and hair from patients with male pattern baldness, alopecia areata and various types of female defluvium capillorum