Where on the scalp should a scalp biopsy be done?

Poor Hair Growth After A Hair Transplant. Where on the Should A Scalp Biopsy Be Done?

I’ve selected this question below for this week’s question of the week. It allows us to review some concepts in the the evaluation of poor outcomes post transplant.

Question

I am a physician and enjoy your articles, videos and podcast immensely. I have a patient with a hair transplant that did not grow well. I think they have LPP or FAPD or some kind of scarring alopecia.

Do you have any tips on where on the scalp I should biopsy?

Answer

Thanks for the question and comment. This general concept of poor growth post transplant is really important to be aware of. Not everyone grows hair spectacularly after surgery. Fortunately, most patients do and hair transplants are a very reliable way of adding back density in the properly selected patient. There are a variety of patient factors, surgeon factors and scalp factors that affect the outcome of surgery. We’ve reviewed these in the past.

So where should a Scalp Biopsy Be Done?

I’m glad you are considering a biopsy as there are so few reasons not to do a biopsy when hair does not grow well post transplant.
In my opinion, the best area to biopsy would be an area that you feel has the morphological features of LPP - outside the transplanted areas. This might be an area showing perifollicular scaling outside the transplanted area. The second best is an area showing perifollicular erythema and white patches outside the transplanted area. The reason this area (outside the transplanted area) is so good is that it is not altered by the surgery. The hair transplant itself can give fibrosis and sometimes even chronic inflammation. Now a good pathologist can work through all this ‘noise’ but it makes the interpretation more challenging.

Some biopsies of scalp that has been transplanted just comes back ‘scarring” alopecia even if it’s not scarring alopecia at all. The pathologist sees some fibrosis and concludes something is wrong.

So having a biopsy from outiside the surgical field is wonderful for this reason.

The third best area to biopsy is an area showing perifollicular scaling inside the transplanted area. You’ll need to warn the pathologist that the patient had a transplant because this needs to be factored into the interpretation.

All in all, in cases like this, a few biopsies may be needed to confirm a more subtle diagnosis. I would encourage you to consider a few biopsies - including those from inside and outside the surgical field and also if there are different morphologies.

Good luck!