Telogen effluvium

Normally only a small share of scalp hairs are in the resting (telogen) phase at any one time. After a shock to the body, such as a high fever, surgery, a major illness, significant stress, a crash diet or having a baby, many more hairs can move into the resting phase together. They then fall out a few months later.

Because of that delay, shedding usually starts two to three months after the trigger, which is why people often do not connect the two. Hair tends to come out evenly from all over the scalp rather than in patches. In many cases the shedding settles within about six months once the trigger has passed, and regrowth follows gradually.

It is sensible to see your GP if shedding is heavy, lasts more than six months or comes with other symptoms such as fatigue, feeling cold or weight change. Blood tests can check for things such as low iron or thyroid problems, which can cause or prolong shedding.