تسجيل الدخول

تسجيل

Biology of hair , Types of hair

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  p154-155

2026-10-04

136

Biology of hair

Types of hair

Pubic hair, arm hair and axillary (armpit) hair have been suggested as an alternative source for drug detection when scalp hair is not available. Various studies have found differences in concentrations between pubic or axillary hair and scalp hair. Comparisons of methadone, cocaine, morphine and phenobarbital concentrations show the highest values to be in the axillary hair, followed by pubic hair and scalp hair. In contrast, in another study the highest morphine concentrations were found in pubic hair (0.80–1.34 ng/mg), followed by head hair (0.62–27.10 ng/mg) and axillary hair (0.40–24.20 ng/mg). The significant differences of the drug concentrations in these studies are explained by a better blood circulation, a greater number of apocrine glands, a totally different telogen: anagen ratio and a different growth rate of the hair (axillary hair 0.40 mm/day, pubic hair 0.30 mm/day).

Beard hair grows at about 0.27 mm/day and is considered a suitable alternative, as it can be collected on a daily basis with an electric shaver and can be used to evaluate the incorporation rate of drugs (Mangin 1996).