Clinicians are seeing a troubling post-COVID side effect in a large number of patients: hair loss.
Brian Abittan, MD, chief of skin and dermatology at the Hair Regrowth Center at Mount Sinai Health System in New York, said he sees multiple patients each week reporting hair loss after COVID-19. “One day passed and I didn’t get asked about it,” Abittan told MedPage Today.
Although more patients explicitly report hair loss after COVID, there is no reliable data describing how many patients experience this phenomenon or what factors put someone at risk. While there are still many unanswered questions about COVID-related hair loss, experts say the good news is that it appears to be temporary, and clinicians should reassure patients that their hair is likely to grow back.
There is some evidence that there is an increased risk of hair loss after contracting COVID. A study published last month in Nature Medicine found that hair loss was one of several symptoms that patients reported to their primary care physicians after COVID. The researchers found that patients with a history of COVID were nearly four times more likely to experience hair loss (hazard ratio, 3.99) than those without the infection. The Lancet estimates that 22% of patients hospitalized with COVID experience hair loss following their illness.
The most common type of hair loss in post-COVID patients is telogen effluvium. “The hypothesis is that COVID-related hair loss is very similar to stress-related hair loss,” Abittan said. Such as surgery, illness or any stressful life event such as moving or pregnancy. Hair goes through three phases in the growth cycle: anagen, catagen and telogen. The anagen phase is the active growth phase, the catagen phase is the transition phase, and the telogen phase is the resting phase of hair loss.
When a larger percentage of hairs on the scalp transfer to this resting stage, resulting in a higher rate of shedding. It’s normal for patients to lose about 100 hairs a day, Abittan said. But with telogen effluvium, patients can lose as many as 300, 500 or even 1,000 hairs a day, he added.
“A lot of times people don’t even notice they come off,” Abbitt said. “But once they shed to a level they notice, then they start counting every hair on their head.”
Hair may start shedding 2 or 3 months after infection, says Alexis Young, MD, a dermatologist at Hackensack University Medical Center in New Jersey. She added that the shedding can last up to six months, and the hair usually takes about a year and a half to grow back.
There are several hypotheses about the cause of infection leading to hair loss in COVID patients, one of which is the increased inflammatory state of the patient. Certain inflammatory markers called interleukins are elevated during COVID, which can cause hair to enter telogen prematurely, Young said.
Because telogen effluvium is triggered by stress on the hair, it may be that patients hospitalized with COVID or on mechanical ventilators experience more shedding than mildly ill patients, she added.
“The more severe cases may be more severe hair loss,” Yang said. However, she added that the causes of hair loss in severe COVID patients can be multifactorial, related to the medications they take or the surgery they undergo. Yang said more research is needed to understand what puts patients at greater risk for severe hair loss.
Other theories about causing COVID-related hair loss include direct entry of the virus into the hair follicle, which may interrupt the growth cycle. Given that COVID causes blood clots, some have also raised the hypothesis that tiny blood clots may also interfere with the growth cycle.
To determine the best treatment option, clinicians should evaluate to make sure there are no other underlying causes of hair loss, such as thyroid problems, Abittan said. Once COVID-19 is identified as a possible cause of telogen effluvium, patients may turn to a number of oral pills and topical treatments—none of which are FDA-approved. However, Abittan says gentle grooming and conditioning are the most effective at promoting hair growth.
Because telogen effluvium is not a scarring process, hair can — and likely will — grow back on its own, Yang added. “There’s really nothing to speed this up,” she said. Young advises her patients to eat a healthy diet and try to reduce stress, which can exacerbate hair loss.
“Most people will eventually grow hair,” Abitan said. “It takes time.”
Patients with chronic coronavirus infections can experience a variety of symptoms, from heart problems to breathing problems and fatigue. While hair loss can be mixed with some other symptoms, Abittan says addressing the problem is important for the patient’s mental health and well-being.
“When someone does experience hair loss, it can be quite dramatic and worrying for the patient,” Abittan said. “It definitely hurts people.”
Amanda D’Ambrosio is a MedPage Today business and Reporter on the investigative team. She reports on obstetrics and other clinical news, and writes features on the U.S. healthcare system. Follow