What causes scarring alopecias like FFA and LLP to reactivate?

Question

QUESTION: What causes scarring alopecias like FFA and LLP to reactivate? After a period of approximately 6 months during which my hair loss from FFA & LPP seemed to stabilize and hair density actually improved, the shedding has now significantly increased again. What causes these scarring alopecias to reactivate months, or potentially even years, after a period of being quiet with no measurable hair loss? Thank you.

Answer

Thanks for the question. There are a number of reasons why a scarring alopecia can re-activate after it was once quiet. Here are the top 5 important points of discussion. 

Reason 1: We simply don't know the reason.

Although not the answer one would expect to hear as reason 1, we need to respect that we don't completely understand scarring alopecia in the present day and age. Often, we simply don't know the reason. Scarring alopecias can activate and become quiet for periods on their own. We often attribute the entry into a "quiet (inactive) phase" as proof that some type of treatment we are using is helping but scarring alopecias can become quiet other own. Similarly, we often attribute worsening as an indication that something we are doing is no longer working, or we're doing something 'wrong.' However, scarring alopecias can become active spontaneously for reasons that are not clear.

 

Reason 2: A second hair loss condition has developed.

Whenever there is worsening hair loss, we need to consider that the loss is actually due to another condition, and not the scarring alopecia. Such a condition is often in the form of a 'telogen effluvium," There is an increased incident of iron deficiency, low vitamin D and even thyroid dysfunction among patients with scarring alopecia. For example, a 2014 study from the Cleveland clinic showed that 29 % of patients with LPP develop thyroid dysfunction compared to 9 % of controls. A second study showed that there are also differences in vitamin D status. I've included these references below. 

Levels of vitamin D, TSH, ferritin, zinc should be checked in any patient who experiences a 'flare' following an extended period of quiescences. 

Reason 3: There has been increased life stress.

There's no doubt in my mind that increased life stress can trigger flares in patents with scarring alopecias. It's not clear why and the link seems more relevant for scarring alopecias such as lichen planopilaris (LPP) and frontal fibrosing alopecia (FFA) than many of the other scarring alopecias. Stress can increase a variety of neuromediators and nerve-related hormones in the scalp which impact inflammation.  

Reason 4: There has been injury to the scalp.

It continues to be an area of limited study, by injury can trigger a worsening or 'flare' of a scarring alopecia.  The medical literature documents injuries such as facelifts and hair transplants as triggering scarring alopecias to worsen. However, many types of injuries can cause the disease to reactivate. 

Reason 5: Medications have recently been started or stopped

A scarring alopecia can become active again on account of a) stopping a mediation that was helping, b) starting a medication that was not used before and c) rarely, changing the brand name of a medication that was helping .

If one has recently tapered or reduced a medication within the last one year and is now noticing a worsening of hair loss, they need to consider that the cessation  or reduction of medication could be responsible for the 'flare'. We see that with slow acting medications like hydroxychloroquine. 

Starting a new medication can sometimes trigger shedding. For example, the addition of minoxidil to the scalp in a patient who otherwise had stable disease, can trigger some shedding. Also some medications such as hydroxychoroquine can trigger shedding in some patients. 

Finally, we rarely encounter a situation where a pharmacy changes the brand of the mediation given to the patient. Instead of getting tablets form company X, they are dispensed tablets from company Y. It appears to be the same medication but for some reason a flare occurs. Even more rarely the wrong dose has been prescribed to the patient and they end up receiving less than intended. This of course can cause a flare.

Reason 6: The scarring alopecia has done from "very slightly active" to "slightly active"

To be truly confident a scarring alopecia is inactive, one needs to observe it for two years. After a period of 6 months of observation with a scarring it being "quiet", we can't actually conclude that it was truly inactive.

I often given an analogy of a car moving down the street as an analogy to understand the speed of hair loss. Suppose one's hair loss is moving forward at 6 miles per hour. For the sake of argument, let's say that particular speed is fast enough to see a change in hair density every 6 months. Now let's say the hair loss slows down to a rate of 2 miles per hour. That's really slow. It's not enough to see a change every 6 months but it is just enough to detect a change in density every 1-2 years. If a patient has hair loss moving forward a 2 mies per hour, and they don't see a change after 6 months, they can not conclude it is inactive. Rather there are two possibilities in such a case: either the scarring alopecia is inactive or it is still very slightly active. A clinical examination of the scalp by a dermatologist or time will declare which is correct.  

CONCLUSION

Thanks once again for the great question. When I teach doctors about the reasons for flares in an otherwise stable patient, I frequently use the memory tool "IM WORSE" to help remember the reasons for a flare. This is summarized below. I've also written about the topic in the attached link:

WHY IS MY SCARRING ALOPECIA FLARING AGAIN?

REFERENCE

Atanaskova Mesinkovska N, et al. Association of lichen planopilaris with thyroid disease: a retrospective case-control study. J Am Acad Dermatol. 2014.

Conic RRZ, et al. Vitamin D Status in Scarring and Non-Scarring Alopecia. J Am Acad Dermatol. 2018.