Multiple biopsies may be needed
Chronic telogen effluvium (CTE) is a chronic hair shedding condition. It typically occurs in women between the ages of 35-60. It is uncommon among men and younger women.
Chronic telogen effluvium is often misdiagnosed, especially in younger women where the presence of increased daily hair shedding so often represents a diagnosis of early genetic hair loss rather than chronic telogen effluvium. Of course, there are exceptions.
Patients are often surprised to hear of the challenges that can exist when one attempts to use a scalp biopsy as the sole means to diagnose CTE. First a scalp biopsy needs to be performed using "horizontal" (transverse) sections rather than vertical sections. This is the only means to get a sense of the ratios of terminal (thick) and vellus (thin) hairs. In CTE, the terminal to vellus ratio (T:V ratio) is often above 8:1 whereas in androgenetic alopecia, it is frequently less than 4:1. If the pathology lab does not process biopsies via horizontal sectioning, one can only get limited information from the scalp biopsy as far as the diagnosis of CTE goes.
Second, if one does perform horizontal sectioning of biopsies, one needs to be aware that more than one biopsy sample might be needed to get an accurate diagnosis.
In 2004, Sinclair et al compared biopsies of 305 women who had 1 horizontal section biopsy vs 207 women who had 3 biopsies done. The key point was that performing multiple biopsies increased the accuracy. With one biopsy, an accurate diagnosis could be confidently made 79% of the time. With 3 biopsies, an accurate diagnosis could be made 98 % of the time.
Conclusion: People with suspected hair loss must be open to the potential that more than one biopsy may be needed to definitively confirm the diagnosis of challenging scalp hair loss presentations. The clinician must also use his or her clinical expertise to assist in formulating a diagnosis.
Sinclair R, et al. The reliability of horizontally sectioned scalp biopsies in the diagnosis of chronic diffuse telogen hair loss in women. J Am Acad Dermatol. 2004.
Dr. Jeff Donovan is a Canadian and US board certified dermatologist specializing exclusively in hair loss. To schedule a consultation, please call the Whistler office at 604.283.1887