Stress, Illness and Telogen Effluvium: Why Hair Sheds Months Later

If your hair started coming out in handfuls a couple of months after something difficult, the delay is the most informative thing about it. Telogen effluvium is a shed rather than a loss, and the gap between the trigger and the shedding is built into how hair grows.

The American Academy of Dermatology draws the distinction directly: hair loss occurs when something stops the hair from growing, whereas shedding is hair falling out. It also gives the baseline most people have never been told — it is normal to shed between 50 and 100 hairs a day, which means seeing hair in a drain is not by itself a finding.

Why the delay happens

Scalp hairs are not synchronised. At any moment most are growing and a minority are in a resting phase that ends with the hair being released, which is why ordinary shedding is a trickle rather than a wave.

A significant physical or emotional event can push an unusually large group of follicles out of growing and into resting at roughly the same time. Those hairs are not lost at that moment; they sit in the resting phase and are released when it ends. That is the delay. The event was months ago; the shedding is the echo.

It also explains the most distressing feature of the condition, which is that the shedding often starts when a person feels they have already recovered from whatever caused it.

The triggers, as the AAD lists them

• Significant weight loss
• Childbirth
• High levels of stress
• A high fever
• Surgery
• Recovering from an illness
• Stopping birth control pills

The list is worth reading twice, because several items on it are things people are pleased about — a big weight loss, a recovery, a birth. A shed after a good event is still a shed.

How long it lasts

The AAD's answer is that within six to nine months the hair tends to regain its normal fullness. That is the ordinary course, and it is the reason the first thing a dermatologist often does about telogen effluvium is explain it rather than treat it.

The important exception is in the same guidance: if the stressor persists, hair shedding can be long lived. A shed that keeps going is usually a sign that whatever set it off has not finished — ongoing illness, a continuing period of acute stress, a nutritional problem, or an untreated condition — and that is a reason to be examined rather than to wait it out.

Where it is confused with pattern baldness

Two mistakes are common, and they run in opposite directions.

Reading a shed as the start of balding. Diffuse shedding all over the scalp does not look like pattern hair loss, which concentrates at the temples and the crown and develops over years. Someone who starts a treatment during a shed and sees the shed stop a few months later can easily credit the product with something that was going to happen anyway.

Reading balding as a shed. The reverse is also common: assuming a slow, patterned thinning is stress-related and waiting for it to resolve. Pattern loss does not resolve, and the treatments with pooled evidence behind it act on follicles that are still producing hair.

The signs that hair loss is not pattern baldness sets out how to tell these apart by distribution, speed and how the scalp looks; the index of hair-loss treatments grades products against pattern loss specifically, and none of those grades transfers to a shed.

What actually helps

The honest answer is that the useful interventions here are mostly not products. Treating the underlying cause is the treatment — resolving the illness, correcting a nutritional problem, letting the body recover from surgery, getting help with the thing that is causing the stress.

Nutritional deficiencies are worth taking seriously precisely because they are correctable, and they are diagnosed with a blood test rather than guessed at. Taking supplements on the assumption of a deficiency is the wrong way round: if there is no deficiency, the supplement has nothing to correct, and the index grades oral hair supplements in its bottom tier for exactly that reason.

What not to do while you wait

Do not start and stop things. A shed that resolves on its own over six to nine months will resolve during whatever you happen to be using, and the product will get the credit. If something is worth trying, it is worth trying deliberately, with a start date written down.

Do not treat a suspected deficiency without testing for it. Iron and vitamin levels are measured, not guessed, and the AAD mentions checking them in the context of investigating hair loss. Supplementing iron in particular is not harmless.

Do not change a prescribed medicine on your own. If a medicine is a plausible cause, that is a conversation with the person who prescribed it.

Do keep photographs. A shed is easier to be reassured about in retrospect than in the middle of it, and a consistent series of photographs is the only reliable way to tell whether density is returning.

Do not judge it in the shower. Washing releases hairs that had already detached, so a wash after several days looks alarming and means very little. The same is true of long hair, which makes any given number of shed hairs look like more.

When to see someone

Go if the shedding has not settled after a few months, if it is getting heavier rather than lighter, if you cannot identify a trigger, or if anything else is happening at the same time — fatigue, weight change, heavy periods, a new medicine, or a scalp that looks red, scaly or sore. The AAD's own line is that a dermatologist can tell you whether you have hair loss or excessive hair shedding, and that is the question at the heart of this page. The next one is what that appointment involves, if the patches you are seeing are round rather than diffuse.