Acute telogen effluvium ("TE") vs chronic telogen effluvium ("CTE"): What's the difference anyways?

Acute vs chronic telogen effluvium: What are the key differences?

Acute and chronic telogen effluvium are different conditions and are the source of much confusion.

Acute Telogen Effluvium

Acute telogen effluvium is a form of excessive hair shedding which typically occurs following some type of event that the hair follicle interprets as a “shock.” Stress, low iron, thyroid problems medications, diets, internal disease and scalp inflammatory diseases can all trigger a telogen effluvium. Many cases of telogen effluvium resolve once the original trigger that caused the shedding in the first place is addressed. If the cause was hypothyroidism, then thyroid replacement might be given. If the actual cause was low iron them iron replacement is given. If the cause is a crash diet, only a balanced diet can help  normal hair growth again. Sometimes, we cannot find a cause and the shedding either continues or stops. Acute telogen effluvium can happen at any age. Children frequently develop acute telogen effluvium from fever. Adults develop from medications, stress, dieting surgeries and scalp inflammation.


Chronic Telogen Effluvium

Chronic telogen effluvium is best called chronic idiopathic telogen effluvium. In fact, anything that makes it sound different than acute telogen effluvium is probably a good thing. This is because chronic telogen effluvium is different than acute telogen effluvium. It’s true that some people simply view CTE as any hair shedding that has gone on for more than 6 months. This is not correct interpretation in my opinion. Suppose a patient has a thyroid disorder and is shedding alot of hair. The patient is busy with work and the kids and has not stepped foot into a doctor’s office to get things checked out for over a year since the shedding started. Should we call this CTE? Not at all. This is acute TE that has not yet been diagnosed. See the difference? Chronic idiopathic telogen effluvium is a hair shedding disorder that happens mostly in women 35-65 whereby the patient develops a sudden onset of shedding. Often a trigger can’t be found. These patients often give a story of once having super thick hair - so thick in fact that the hairdresser would joke that they should be charged double. Patients with CTE shed and shed - some days alot and some days only a little. Their blood tests are normal. They look like they have alot of hair when they walk into the office. Examination in the clinic can look fairly normal although some patients do have marked recession in the temples (so called bilateral temporal recession). We don’t know what causes CTE. It’s a complex hair shedding disorder. It can last a very long time but some do experience spontaneous resolution. We don’t yet know how best to treat although minoxidil (topical or oral), low level laser, biotin, hair and nail supplements, lysine, B6 are all part of the treatments. Provided patients with CTE don’t have another hair loss consultation going on as well (like androgenetic alopecia), patients with CTE can be reassured that they won’t develop progressive balding over time. They may or may not easily get back their density but they won’t get worse. Photos are essential to prove to the patient and hair specialist that the hair is not getting worse.


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



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