More patients are presenting to their doctors with hair loss after covid infection. Here’s what we know so far.
Doctors are seeing an increasing number of patients experiencing significant hair loss after covid – with many losing half of their hair volume.
Melbourne dermatologist Professor Rodney Sinclair, who co-authored an article on the subject in the Journal of The American Academy of Dermatology, said he was seeing about five patients every day with postinfectious telogen effluvium. Some also had trichodynia.
On average, each patient had lost about half of their hair volume, and Professor Sinclair said virtually all were women, regardless of hair length.
But he said there was nothing to suggest men were not as affected by the problem; it was just more likely that women noticed it more and were more likely to seek advice.
“It’s really with all hair, but they [women with long hair] tend to notice it more because it’s more spectacular with the long hair.
The hair loss was often accompanied by trichodynia, a tingling and/or burning sensation on the scalp, Professor Sinclair said.
He said there was still no clear pattern as to which patients were more at risk of hair loss after covid than others.
“I don’t think there’s been any quick prospective studies where they’ve got 100 people with covid who were followed up six weeks later to see how many got the hair loss,” he said.
However, he said he expected that it was “very common”. And the reason it occurred might not be complicated.
“It’s what they call a post-stressful event. But it’s got nothing to do with emotional stress,” he said.
“If you stress the body physically there are defence mechanisms to try to preserve critical functions and they will often divert metabolic activity away from non-essential functions.
“This is one of those areas where the body diverts energy and calories away from investing in hair, so it can preserve vital organs.”
And it’s not a problem limited to covid, Professor Sinclair explained.
“We see it after people have had very high fevers, we see it after people have had prolonged surgery, we see it after they have lost litres of blood,” he said.
“And so it’s a very common thing that normally occurs about three months after the triggering event.”
One difference with covid-related hair loss was that onset could begin much earlier than the three-month mark.
The original study Professor Sinclair co-authored also suggested that the addition of trichodynia as a symptom was usually associated with loss of taste (ageusia) and/or smell (anosmia) from the covid infection.
“We see a number of our patients have trichodynia but not all,” he said.
Professor Sinclair and his colleagues collected data from 128 patients. Telogen effluvium was observed in 66.3% of the patients and trichodynia in 58.4%. Trichodynia was associated with telogen effluvium in 42.4% of the cases and anosmia and ageusia in 66.1% and 44.1% of the cases, respectively.
In 62.5% of the patients, the hair signs and symptoms started within the first month of covid diagnosis, and in 47.8% of the patients, these started after 12 weeks or more.
They also found that the severity of the post-viral telogen effluvium might be influenced by the severity of the covid infection.
The good news was, however, that most cases resolved within a few months.
“Acute telogen effluvium undergoes remission within 3-6 months of onset unless associated with androgenetic alopecia, whereas chronic telogen effluvium persists beyond six months,” the authors wrote.
Professor Sinclair said most patients would recover completely assuming there was no underlying tendency to androgenetic alopecia. And if people had slowly progressive age-related hair loss, this would accelerate it, leading to an incomplete recovery.
While time would resolve most cases, he said, there were things people could do to speed up the regrowth, including the use of over-the-counter minoxidil, applied directly to the scalp. Oral minoxidil might also be useful, he said.
“A number of them [his patients] are prescribed sublingual minoxidil, which is a treatment that we use for pretty much all forms of hair loss and that can be used to shorten the duration of the hair shedding and hasten recovery because it also makes the hair grow a little bit faster,” Professor Sinclair said.
He said it was important to check whether anything else might be contributing to the hair loss, such as iron deficiency or thyroid disease.
Professor Sinclair said there was no need to treat trichodynia with topical steroids. It was also important to reassure them that emotional stress alone would not cause the hair to fall out.
“If the patient can be reassured and if the patient is happy to wait it out that’s perfectly fine,” he said.
“If the patient is very distressed by it, and some of them certainly are, then they [the doctor] may consider prescribing minoxidil lotion.
“There are also topical prostaglandin patients can get from a hairdressing salon. It’s a Kerastase product called Densifique and you can just walk into a salon and get that.
“And then if they’re really distressed, or they don’t recover completely, or it goes on longer than you think, it is normal then to refer to a dermatologist.”
Journal of The American Academy of Dermatology 2021, online 21 August
