Does hair density always come back after a telogen effluvium?
One of my favorite hair loss topics centers around what happens to a person’s hair density 9 months after a telogen effluvium. Broadly speaking, this is topic is called the “sequelae of telogen effluvium.”
Before we begin, I will remind you that Telogen effluvium (TE) is a hair shedding condition whereby a patient notices more hair coming out of the scalp than normal on a daily basis.
Most would say that 6-9 months after a TE, the hair density improves back to normal. This is true only if all the correct “triggers” of the TE can be found. Many times a trigger can’t be found and many times even if a patient or physician think they know the trigger, it’s not actually the trigger. For example, many patients who think their low vitamin D or low iron levels are the sole cause of their TE may find the shedding does not improve simply by supplementing vitamin D and iron. The reality is that unless the exact trigger or triggers can be found it is likely the shedding will not stop. Typical triggers include thyroid problems, dietary issues, low iron (sometimes), stress, medications, scalp diseases (seborrheic dermatitis) and over 700 internal conditions (infection, joint disease, lupus, cancer).
But two other “sequelae” can occur including the development of chronic shedding and coming to be diagnosed with another completely separate hair loss condition.
Sequelae 1: Chronic Shedding
For some patients, despite fixing all the suspected triggers, the shedding persists for more than 6-9 months and enters what we call “chronic shedding.” For some patients, the shedding eventually just stops and density returns to normal. This can happen without any particularly good reason and is very exciting for patients when it does occur. For other patients with chronic shedding, a trigger is eventually found and addressing that trigger causes the shedding to improve. This might be a patient who discovers a chronic underlying medical condition and addresses it. Hundreds of such examples exist. But some patients continue to shed for many many years despite their being NO obvious trigger and despite their health being very good. We call this chronic idiopathic telogen effluvium or simple chronic telogen effluvium (CTE). In my mind CTE is a specific condition when no obvious ongoing trigger is present.
Sequelae 2: Development of a Second Condition
Finally, one additional sequelae needs to be considered - and that is the possibility that hair density does not return to normal because a second hair loss condition develops. It's not that the shedding condition caused the second condition but rather that the second condition was there all along. This is more common than appreciated. For some individuals with a genetic predisposition to androgenetic alopecia, chronic shedding can speed up the development of balding. This is often referred to by a bizarre phrase whereby you might hear it said that chronic shedding “precipitates” androgenetic alopecia. I prefer to refer to the phenomenon in our clinic as “AFMPS” or accelerated follicular miniaturization from prolonged shedding because it makes more sense than using the word “precipitation.” But the concepts are the same: patient with chronic shedding who are destined to develop male and female balding in the more distant future may find that they develop androgenetic balding a bit sooner. We see this commonly after various effluviums. Why do some women after months and months of shedding find their density does not return despite fixing the suspected trigger? AFMPS or the unexpected arrival of genetic hair loss. This concept is too often forgotten or not understood.
One must also keep in mind that in addition to genetic hair loss, other conditions can rarely also declare themselves after a patient develop shedding. Chronic shedding diagnosed as a TE may rarely be the earliest stages of a scarring alopecia or the earliest stages of alopecia areata (diffuse alopecia areata or alopecia areata incognito). A physician must always keep these entities in the back of his or her mind when evaluating a patient with chronic shedding.
In summary, telogen effluvium can either be uncomplicated or complicated. We can’t tell patients that their shedding will stop in a few months and everything will return to normal. We can of course hope for it. Fortunately most patients do follow an uncomplicated story of shedding. Shedding —-> fix trigger(s) ——> shedding stops ——> hair grows back. But this is not the case for all.
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