Utility of a Scalp Biopsy Depends on the Stage of the Disease

A Scalp Biopsy is Not Always Useful

A scalp biopsy is not always useful.

Scalp biopsies are particularly useful when the clinical examination and patient history of hair loss do not allow the clinician to arrive at a final diagnosis.

However, even then, a scalp biopsy is not without limitations.

Scalp biopsies are most accurate when a hair loss condition has progressed “far enough” in its development that a pathologist can identify several typical features under the microscope. In the very early stages of a hair loss condition, a scalp biopsy is often less helpful because many features of the condition will not yet be present under the microscope.

Limitations Exist in Very Early and Very Late Disease

For example, in the “very very early” stages of frontal fibrosing alopecia a pathologist may not identify any loss of sebaceous glands and may not capture much in the way of perifollicular fibrosis. If lucky, the pathologist looking at a slide of early FFA may capture some inflammation around vellus hairs. In these very early stages, the clinical examination is probably more helpful than scalp biopsy.

Similarly in the “very late” stages of most hair loss conditions, it also becomes more and more difficult to find key diagnostic features in a scalp biopsy. For example, end stage lichen planopilaris may look like the end stage of any scarring alopecia with loss of sebaceous glands and destruction of hairs. If the practitioner takes a biopsy from an area of severely scarred LPP, the practitioner should not expect the pathologist to render a diagnosis of lichen planopilaris: Rather, the pathologist may only be able to say the sample is some kind of “scarring alopecia.” All end stage scarring alopecias look fairly similar.

Final Comment

It’s important to understand the limitations of a scalp biopsy. They are wonderful diagnostic tools in the right scenario but should never be viewed as mandatory for every patient with hair loss. Scalp biopsies are not always so helpful in the very very early stages of a hair loss condition and not so helpful in the very very late stages of a hair loss condition.