Hair shedding in women: how much is too much?

DEAR EDITOR, Human hair growth is cyclical but asynchronous. Women normally shed 50–150 hairs over a 24-h period. Most shedding goes unnoticed. Women who complain of excessive hair shedding, especially after washing their hair, may have either an increase in the actual amount of hair falling or an increased awareness of their hair fall. Changes in actual amount of hair fall occur in anagen effluvium, acute and chronic telogen effluvium, alopecia areata, cicatricial alopecia and female pattern hair loss (FPHL). A change in perception of hair loss may occur with a change in hair length, a change in bathroom lighting or flooring, or a concern about hair loss. Women anxious about hair loss may start to notice, collect and count shed hairs. FPHL is the most common cause of hair loss encountered in clinical practice and has a negative impact on quality of life. FPHL is a complex polygenic disorder characterized clinically by diffuse hair thinning over the mid-frontal scalp, on dermoscopy by > 20% variation in hair fibre diameter and fewer hair fibres emerging from each pore over the affected scalp, and histologically by hair follicle miniaturization with fewer terminal hairs per follicular unit. Some women present with increased hair shedding without thinning. Approximately 60% of these women will have androgenetic alopecia on scalp biopsy. Hair follicle miniaturization is reversible initially but becomes irreversible. Treatment success is most likely in early FPHL. A tool to identify increased hair shedding would facilitate early diagnosis of FPHL. The hair pull test, while widely used, does not reliably discriminate normal from excessive hair shedding. Furthermore, women may be better able to assess hair shedding than hair volume. To measure hair shedding we developed a visual analogue scale (VAS) by dividing a bundle of 900 shoulder-length hairs into six piles of various sizes, which were each counted, photographed and arranged in order of size (Fig. 1). To assess observer reliability, we piloted the hair shedding scale in 50 women attending a hair loss clinic for scalp biopsy. The women looked at an A4 page containing the six photos of hair bundles and were asked to point to the photograph that best correlated with the amount of hair shed on a wash day and the photo that correlated best with the amount shed on a non-wash day. The frequency of hair washing was also recorded. The results were scored on a scale of 1–6. The women’s hair shedding was rescored on return 1 or 2 weeks later for removal of their sutures.