Delayed telogen replacement in a boy's scalp.

BACKGROUND

In case the shedding telogen hair is not replaced in time by a terminal anagen hair, an empty space results.

OBJECTIVE

To verify whether the phenomenon is present in prepubertal subjects.

METHODS

From July 1996 to May 1997, an 8-year-old boy was submitted monthly to the phototrichogram technique. Sixty hairs were monitored throughout the study.

RESULTS

52% of all studied hairs were terminal anagen hairs throughout the study and additionally 22% were in a regular hair cycle. Vellus hairs and empty spaces were observed in 18 and 8% of follicles, respectively. In 2% of hairs, vellus hairs and empty spaces were associated.

CONCLUSIONS

Vellus hairs and empty spaces are present even in children. Without gonadal androgens and expression or induction of 5alpha-reductase in the prepubertal scalp, they are unlikely to herald androgenetic alopecia (AGA) but could reflect a physiological phenomenon of 'true resting' of a small proportion of scalp hair. Androgens may increase the phenomenon which may account in part for AGA development.