Do I Need a Scalp Biopsy? A Closer Look at the Criteria and Indications for Scalp Biopsies

Should I be having a scalp biopsy? Do I need a scalp biopsy?

Scalp biopsies are not needed for everyone with hair loss. In fact, only a minority of patients really need scalp biopsy to determine the diagnosis. In my clinic, I only do scalp biopsies in a very small proportion of patients - somewhere in the order of 10-15 % of patients.

When patients hear me say that biopsies are not common in my office, they usually ask “Well how does a hair specialist make the diagnosis?

Well that answer is easy! The hair specialist must use information obtained from the patient’s story (called the ‘history’), together with the patent’s scalp examination and blood test results helps solidify the diagnosis. I refer to this as the Diagnostic “S.E.T.” (story, examination, tests).

See previous article: The Diagnostic SET: Making the Diagnosis of Hair Loss.

Sometimes, the so called diagnostic set helps narrow down the diagnosis to just a few possibilities but the exact final diagnosis still can’t be precisely determined. This is the situation when a scalp biopsy can prove very useful to narrow down the possibilities even further.

Criteria and Indications for having a scalp biopsy

A scalp biopsy may be helpful if ANY of the following are found to be true:

1. The diagnosis can not be confidently determined after careful review the patient’s medical history, examination of the scalp with dermoscopy and review of blood tests (i.e. after careful review of the diagnostic set). In many cases, the diagnoses still being considered by the hair specialist can look identical and a biopsy is needed to differentiate between them. For example, in a patient with chronic hair shedding that is not getting better, a biopsy might be helpful to determine if the cause of the shedding is due to telogen effluvium, androgenetic alopecia, alopecia areata diffusa, or lichen planopilaris. These 4 conditions can usually be distinguished with careful attention to the patient’s history and scalp examination finings - but not always ! To give another example, sometimes patients with red, itchy or tender scalps benefit from a scalp biopsy because conditions such as scarring alopecia, lupus, psoriasis, contact dermatitis, seborrheic dermatitis can look similar.

2. The patient has received different diagnoses from two or more specialists. For example, if one specialist feels the patient has genetic hair loss and a second specialist feels the patient has telogen effluvium, a scalp biopsy might help determine which specialist is correct so that the patient can get started on the correct treatment. A patient needs an accurate diagnosis plain and simple.

3. The patient has received one or more different diagnoses in the past but the hair specialist examining the patient now feels these were actually incorrect diagnoses. For example, if a patient has been told they have androgenetic alopecia, but the hair specialist examining the patient today feels that the diagnosis is actually something else, a biopsy might be indicated.

4. The patient has already had one or more scalp biopsies but the diagnoses offered by the pathologist do not seem consistent with the clinical picture and clinical diagnoses that are being considered. For example, if the biopsy returns showing evidence of a scarring alopecia but it does not seem that this could possible be true based on the patient’s story and what the scalp looks like, a repeat biopsy might be indicated.

5. The patient received a diagnosis in the past but is not responding to treatment in a manner that would be expected for that diagnosis. For example, if a patient received a diagnosis of telogen effluvium due to a thyroid disorder and hair shedding is continuing for many months after the thyroid issues were completely corrected, one might consider revisiting the diagnosis again. A biopsy may be indicated.

Common Myths and Misconceptions

A biopsy is NOT necessarily needed just because the following are found to be true:

1. There are no triggers found for the hair loss. Many hair loss conditions do not have identifiable triggers. If the diagnosis can be made with proper use of the diagnostic set (history, scalp examination and blood tests) a biopsy is not needed for all cases of hair loss that lack a triggering event. If the cause of the hair loss can not be precisely determined following careful review of the diagnostic set, a biopsy is required.

2. Severe hair loss. If the diagnosis can be made with proper use of the diagnostic set (history, scalp examination and blood tests) a biopsy is not needed for all cases of severe hair loss. If the cause of the severe hair loss can not be precisely determined following careful review of the diagnostic set, a biopsy is required.

3. Acute hair loss. If the diagnosis can be made with proper use of the diagnostic set (history, scalp examination and blood tests) a biopsy is not needed for all cases of acute hair loss. If the cause of the severe hair loss can not be precisely determined following careful review of the diagnostic set, a biopsy is required.