Do scarring alopecias halt once inflammation disappears?
Many of the so called ‘primary scarring alopecias’ are associated with inflammation under the scalp. Conditions like lichen planopilaris, frontal fibrosing alopecia, discoid lupus, central centrifugal cicatricial alopecia, pseudopelade, folliculitis decalvans are all associated with inflammation.
This inflammation is present both histologically (under the microscope) and clinically (we see it on the surface of the scalp). The clinical disappearance of inflammation is always a good sign. The disappearance or reduction of redness, scaling, pustules, are all good signs that inflammation is going away and that treatments are helping.
Reduction of inflammation in necessary but not always sufficient to stop the disease.
The first step in treating scarring alopecia is to get rid of these signs of inflammation. It’s where we start as goal number 1. We try to get rid of the inflammation and see if the hair loss will stop. However, we need to keep in mind that sometimes even when the scalp returns back to quite a normal in appearance (minus the permanent scarring), it’s possible for the disease to still continue.
Fortunately for everyone - this is not the normal scenario.
The normal and typical scenario is for the disease to halt once inflammation disappears. However, there are situations where we stop the inflammation quite well but the hair loss grumbles onwards. There are several things that must be considered when this happens.
Consideration 1: Inflammation is still present under the scalp
Sometimes in situations where clinically the disease seems pretty quiet or inactive, the patient still experiences hair loss. Granted hair loss in this scenario is usually quite slow if it occurs at all. But sometimes there is inflammation going on under the scalp at varying degrees that could, at least theoretically, be driving further hair loss. We don’t in the present day and age have a way of picking out an inflammatory cell from the scalp and asking it whether it is responsible for hair loss or not. That’s simply not possible. But we do have situations where there is a tiny bit of inflammation present and the patient has not lost a strand of hair in years and another situation where the same amount of tiny bits of inflammation are present in the scalp and the patient is still losing hair. Why these differences occur is still a mystery.
Consideration 2: Other non-inflammation based mechanisms are operative
Inflammation seems to be at the center of the mechanisms that operate in scarring alopecia. However, we need to be humble to the fact that that we really understand very little about these diseases (despite our feeling that we are getting closer). There are likely a variety of mechanisms that contribute to the progressive depletion of stem cells in scarring alopecias. Some of these may be dependent on inflammation and some others might not be.
In the present day, clinicians treating scarring alopecia must have as their goal number 1 the removal of inflammation from the scalp. We need to help the patient stop their itching. We need to help them stop their burning and tenderness. We need to get rid of redness from the scalp and get rid of scaling and pustules. Fortunately when we achieve all this - we stop the scarring alopecia disease. But we don’t always. Tiny bits of inflammation under the scalp can still drive progression of scarring alopecias in some cases. In addition, there may be a variety of cytokine, chemokine, and endocrine changes that drive stem cell depletion even in the absence of gross inflammation.
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