Short Cycling (Rapid Cycling) Telogen Effluvium

What is short cycling telogen effluvium ?

I am often asked by patients what is meant by short cycling telogen effluvium?

“Short cycling” and “fast cycling” telogen effluvium are terms that were created on the internet and perpetuated on the internet. They are not formal medical terms that you will see in textbooks and not something you will hear in hair loss clinics of the world. The terms were invented by patients with hair loss quite some time ago - at least 15 years ago and maybe even longer.

But, in my opinion, the terms are useful.

Whoever made them up has created an interesting term to simply describe what some people with telogen effluvium see when they examine their shed hairs.

Most patients with telogen effluvium shed alot of long hairs. Patients who feel they have ‘short cycling’ or ‘fast cycling’ telogen effluvium shed many long hairs too - it’s just they also shed a great deal more short hairs than would be expected. Typically, these short hairs in short cycling telogen effluvium are about 5-7 cm.

So that’s the basics of “short cycling” and “fast cycling” telogen effluvium

Now for the complex part that does not get talked about. I see short cycling TE happening in three situations:

1. A TE that is slowly resolving
2. A short anagen syndrome-like TE that is not resolving
3. A TE that is precipitating AGA or has the propensity to do so in the future.

Let’s take a look at this in a bit more detail.

Mechanism 1: Short hairs are seen A TE that is slowly resolving

Here, there seems to an increased propensity to lose 5-7 cm hairs as the patient’s telogen effluvium resolves. It’s not clear why but for some people it appears it takes a while before hair cycles reset properly. Patient’s lose some shorter hairs for a while and then eventually when the TE comes to a complete halt, the hair shedding goes back to a small number of long hairs.

Mechanism 2: A short anagen syndrome like TE

Some people with telogen effluvium develop a form of telogen effluvium that actually leads to shedding of shorter hairs. It’s an uncommon mechanism but it does occur! It’s called a short anagen syndrome like mechanism. A common example is people who develop shedding with use of medications known as retinoids. Retinoids cause hair shedding in a very small proportion of patients who use the drug (not everyone). The drug causes a shortening of the growth phase (anagen phase) and thereby causes hairs to be shorter and shed more often - and sometimes it does both.

By way of review for those who don’t know, there is not just one mechanism for telogen effluvium. No, contrary to what many believe, TE doesn’t “always” just happen three months after some trigger. That’s the most famous mechanism and so that’s why many know this fact, but that’s not the only way hair shedding occurs!

Dr. David Headington proposed that there five main mechanisms of telogen effluvium. These include (1) the immediate anagen release type of TE, (2) the delayed anagen release type of TE, (3) the shortened anagen type of TE, (4) the immediate telogen release type of TE, and (5) the delayed telogen release type of TE.

Short anagen syndrome is one of the 5 well known mechanisms of TE that a research has uncovered. Sometimes that’s why people shed shorter 5-7 cm hairs.

Mechanism 3: A TE that is precipitating AGA or has the propensity to do so in the future.

I am not all that concerned most of the time when patients with a diagnosis of telogen effluvium shed 5-7 cm hairs for a defined period of time - like 3-12 months.

However, I am generally concerned about patients with persistent “short cycling” telogen effluvium when one of two conditions are met:

a) the patient notes that after waiting 6 months or more for his or her TE to resolve (after correcting what they feels is the trigger), the shedding of hairs seem to be getting shorter and shorter. In other words, the hairs that were once 5-7 cm in length are now 3-4 cm in length.

b) The patient feels that hair density on the scalp keeps dropping even though the suspected trigger was fixed more than 6 months ago. In this case, there are few sprouts of new hair seen on the scalp … or the sprouts that do occur are not leading to a slow and steady improvement in hair density.

Both of these situations speak to the possibility that the patient has an evolving androgenetic alopecia. Now of course they might not have androgenetic alopecia developing, but this possibility needs to be exhaustively explored by the hair specialist. In far more rare cases, another diagnosis (ie scarring alopecia) is present and responsible for the failure of regrowth.

Summary

I first heard about “short cycling” or “rapid cycling” telogen effluvium many, many years ago. It became clear that the term was invented by patients probably 20 or so years ago. it is an interesting term that still gets carried from year to year.

It’s pretty interesting how this term even came about.

The term “short cycling” or “rapid cycling” telogen effluvium refers to a phenomenon whereby patients shed hairs and notice that these shed hairs are much shorter than their typical long hair. There are many reasons for this and some are temporary and some are permanent.

A full scalp examination together with review of the patient’s history and review of blood tests will help determine the exact reason why someone has an apparent “short cycling” (“rapid cycling”) telogen effluvium.