1. Does COVID 19 infection cause people to lose their hair? It’s certainly possible. We still don’t know all the answers pertaining to the relationship between COVID 19 and hair loss yet, because this particular virus is new (hence the name “novel” for the SARS-CoV-2 coronavirus). It appears that most people who acquire COVID 19 infection do not lose hair. In fact, we are now learning that a very large proportion of the population who acquire the SARS-CoV-2 coronavirus are actually asymptomatic. However, there are many patients who experience hair loss following COVID 19. So far, it appears that these are more likely to be patients whose health has been more severely affected by the disease - particularly those with higher fevers, those who need hospitalization, those with greater severity of disease (more days in bed), those with greater severity of pneumonia, those with longer hospital stays (if hospitalized), and those who have more than 1 organ systems affected by the disease such as heart, liver, kidneys or blood clotting systems.
The reality is - we don’t know all the answers yet. We need good studies to better evaluate the frequency of hair loss in patients recovering from COVID 19. 2. What demographic of patients are most likely to have hair loss once they do test positive for COVID 19? Good studies pertaining to hair loss and COVID 19 have yet to be done - at least yet to be published. Over the past many months, researchers have come to understand the risk factors for acquiring COVID 19 including age, race, male gender, underlying medical conditions (cancer, diabetes, obesity, COPD, heart disease, sickle cell disease, immunosuppression) poverty, crowding, pregnancy, and smoking, However, these are only the risk factors that put a person at higher risk to acquire the disease in the first place. We don’t fully understand what risk factors predict hair loss once a person actually gets COVID 19 disease. Based on my view in treating patients and the global understanding of COVID 19 to date, it would appear that the more ill the patient is, the greater the risk of hair loss after COVID 19. Furthermore, the higher the fever, the greater the risk of hair loss as well. Simply put - patients who are profoundly affected by COVID 19 are the patients who seem to be most at risk for getting hair loss. Other less affected patients seem to experience hair loss too - albeit less frequently and less profoundly. 3. How important is COVID 19 related fever in causing hair loss? Fever is one of the most common symptoms of COVID 19 (depending on the study). Fever is probably among the more important “triggers” for hair loss although more studies specifically related to COVID 19 are needed. This seems to be particularly true for fevers above 102.5 F (39.2 C). For those not aware, the medical community actually learned a lot about the relationship between fever and hair loss in the Spanish Flu Pandemic in 1918-1919. In 1919, H.H. Hazen reported in the Journal of the American Medical Association 50 people with hair shedding after the Spanish flu. 47 were women. For 90 % of these individuals, a fever above 102.5 F (39.2 C) was felt to be the trigger. The hair shedding started about 9 weeks after the fever started. All patients experienced rapid regrowth of hair. For over 100 years, this study has remained a frequently referenced study about the cut off for fever that is most likely to be associated with telogen effluvium in adults. 4. How soon after acquiring COVID 19, does hair loss occur? If hair loss does occur, it appears to occur between 7-16 weeks after infection. The typical time course is about 10-11 weeks. Most people who test positive for COVID 19, however, do not develop hair loss. 5. Why is there such a delay between infection with COVID and hair loss?
The type of hair loss that COVID 19 causes is called telogen effluvium or simply “TE” for short. This particular mechanism of hair loss has been very well studied over the last 100 years. It is now well known that 2-3 months after the body experiences any sort of stressful ‘trigger’ that hair shedding can occur. These ‘stresses’ can be physiological stresses or psychological stresses. Common causes of TE include emotional stress, low iron levels, thyroid disease, starting a new medication, dieting, weight loss, internal illness. The latter category of internal illness includes infections - including those giving fevers. 6. Is it the virus that is infecting the hair and causing the hair loss or is there some other indirect reason for the hair loss? For most people who report hair loss after COVID 19, it does not seem to be the virus itself that is directly causing the hair loss. We actually don’t have any good evidence that the virus is found in and around the hair follicles - so the effects seem to be due to the stress the body feels on account of the infection and the chemicals the body products due to the infection (cytokine storm). When a patient with COVID 19 reports hair loss, we need to enquire about the severity of their illness, the height of their fever, the duration they were sick, whether or not they were hospitalized, what medications they received, and how much weight they lost due to their illness. These all contribute to the physiological (as well as psychological) stress the patient experiences. Because the virus is novel, there could be other mechanisms for the hair loss that we haven’t yet come to understand. We are now learning the blood clots in multiple organs are part of the disease process. Whether blood clots (thrombosis) could contribute to the pathogenesis of hair loss in COVID 19 patients needs to be explored. Biopsies of hair loss in patients recovering from COVID 19 have not been well described. 7. How long will the shedding last in a patient with COVID 19 related shedding? Shedding lasts about 3-6 months and then gradually returns to normal daily rates in most. Shedding from COVID 19 is similar to other shedding patterns due to a diagnosis of telogen effluvium. It starts 7-12 weeks after infection, lasts 3-6 months, and then shedding progressively returns back to normal and hair grows back. For some, it may take up to 9 months but this is unusual. 8. What should a person do if they have hair shedding after infection with COVID 19?
Anyone with hair loss needs proper evaluation. This includes a full review of their story, an examination of the scalp and a review of recent and prior blood tests. There are a very large number of reasons why a patient with a recent diagnosis of COVID might be losing hair. These are divided into two broad categories including a) reasons related to the infection and b) reasons unrelated to the infection. a) Reasons related to the infection include the fever, the body’s response to the infection (cytokine storm), the physical and psychological stress, weight loss, new medications received. In addition, if the COVID 19 infection has caused effects on other organ systems, this too may be a reason for hair loss. For example, COVID 19 may cause dysfunction in organs such as the liver, kidneys, thyroid gland and these abnormalities can cause hair loss if severe changes occur. These sorts of changes tend to occur only in the most severe cases. b) Hair loss may be completely unrelated to the COVID 19 infection and this must always be kept in mind. Patients may have hair loss from a completely different and coincidental reason. Genetic hair loss, other causes of telogen effluvium, alopecia areata, and scarring alopecia all give shedding. A patient who enters the COVID 19 era with very mild scarring alopecia may find that the stress of the COVID 19 pandemic makes their scarring alopecia symptoms worse. But the infection itself was not the initial cause of the scarring hair loss. In addition to proper evaluation and examination, anyone with hair shedding needs blood tests for basic labs such as thyroid and ferritin (iron) and hemoglobin. Other tests may be important to consider as well depending on the story uncovered during the history. For example, a person who experienced chronic diarrhea as part of their COVID 19 symptoms may benefit from zinc testing. A patient with a long hospitalization and marked weight loss may benefit from a more thorough set of blood tests for vitamins and minerals. Nothing replaces a proper evaluation and workup of hair loss.
9. What treatments are needed if it’s discovered that a person has a telogen effluvium from COVID 19? Fortunately, most patients with hair loss from COVID 19 will experience hair regrowth back to the same density the hair was like before COVID 19 infection occurred - even without medical treatment. It is indeed good news that telogen effluvium is a temporary condition for the vast majority of people. Once the trigger that causes the TE is fixed or removed, the hair grows back. When infections are resolved, and no longer affecting the body, the hair grows back. There are some important exceptions to the rule that hair always grows back. Patients with ongoing medical issues after COVID 19 may have a slightly greater chance of not experiencing complete regrowth or they may experience some degree of ongoing shedding. This does not happen often but it’s important to be aware that not all patients with telogen effluvium get the hair back to 100 % the same density. Some have ongoing shedding, which is called chronic telogen effluvium. Patients with a diagnosis of androgenetic alopecia before the COVID 19 infection occurred may find that the hair density does not quite return back to what it was like before the COVID 19. Anyone with ongoing shedding beyond 6 months should see their dermatologist again for another careful review. Options such as topical peptides or laser may be helpful for some with ongoing shedding issues post COVID. Good studies have not been done. Even though patients with telogen effluvium from COVID don’t require medical treatment, everyone benefits from supportive care of some kind. Hair loss is extremely distressing and the hair loss from COVID 19 strikes at a time when patients feel they have already gotten over a tremendous life hurdle. Some patients recovered from COVID 19 have little energy left to deal with the emotional distress that now comes with hair loss. All patients with hair loss need our support -and this is particularly relevant to patients recovered from COVID 19 who now have hair loss. 10. If I have hair loss during this COVID 19 pandemic should I get tested for COVID 19? It’s certainly important to be attentive to any changes in symptoms during the pandemic. However, most people who are experiencing hair loss during the COVID 19 pandemic are not going to find that their hair loss is due to COVID 19. The most common symptoms of COVID 19 are fever, cough and fatigue. Other symptoms may be present as well including shortness of breath, headaches, muscle aches, loss of smell, sore throat, and diarrhoea. These main symptoms are generally present within 5-10 days after being infected. Hair loss, in contrast, occurs in only a small proportion and if it does occur at all - it generally occurs about 60-100 days alter being infected with COVID 19. Most people who have concerns about hair loss have hair loss from other reasons besides the COVID 19 infection. Certainly, the hair loss may still be related to some aspect of the COVID 19 pandemic. The stress of the new COVID 19 world, job loss, financial difficulties, social isolation, weight changes all can cause tremendous physiological stress on the body which can trigger hair loss. So, it’s possible that the COVID 19 pandemic contributes to hair loss without the person actually having hair loss from COVID 19 infection. But the same conditions that happened before the pandemic can happen during the pandemic. Hair loss can occur from dozens and dozens of reasons and everyone who is experiencing hair loss needs proper evaluation. In summary, a patient with hair loss should speak to their physician to have a thorough workup for the causes of hair loss. It’s unlikely that testing for COVID 19 at this point will be useful unless a patient has current symptoms of COVID 19. COVID 19 screening is still appropriate for all patients.
SUMMARY AND CONCLUSION
The SARS-CoV-2 coronavirus is new and there is a great deal we still don't understand about it and how it affects the body. We are now coming to recognize that hair loss is a symptom of some with COVID 19 infection - particularly those who have been more severely affected by the disease. Hair loss is typically in the form of a telogen effluvium which gives shedding 2-3 months after the infection. Complete resolution of shedding is the norm for the vast majority of patients.
Written by Dr Mike Ryan, Consultant Trichologist