The main symptoms of Covid-19 are by now well known – a persistent cough, a high temperature and loss of taste or smell. But some people who have been infected with Covid-19 have also reported a new long-term effect: hair loss. But how do you define hair loss and what could be the cause of this increase in people reporting hair loss? Dr Rina Davison, Consultant Endocrinologist at The Holly, takes a closer look.
Try this test out at home: run your fingers through your hair, then count the number of strands that come out. If it’s five or less, that’s normal. But if there are more than five, and this is persistent, it’s important to make sure that all treatable causes have been assessed before the hair thinning becomes a permanent progressive condition.
The news headlines about suffering from Covid-related symptoms long after infection focus on fatigue, brain fog and muscle aches. Another less well known symptom is devastating hair loss. The most common form of post-Covid hair loss is termed “telogen effluvium” or “shock” hair loss. This is when the growing phase of hair switches prematurely to a resting or shedding phase and a large amount of hair is lost very quickly. It is thought that high fevers with Covid-19 triggers this pattern of hair loss but there are many other triggers to this type of generalised hair shedding such as bereavement, redundancy, moving house, and stress (all additional consequences of the pandemic).
Coronavirus infection can also lead to patchy hair loss, or alopecia areata, which occurs when the body treats hair as a foreign object and attacks it. It’s not known exactly what causes this, but one theory is it’s triggered by the virus overwhelming the immune system and causing it to malfunction.
Hair loss is not just a cosmetic symptom however, and it is important to regard it as a possible sign of another hormonal or nutritional imbalance in your body. Covid-19 has recently been reported to affect the thyroid gland, causing neck pain and swelling and sometimes difficulty swallowing. If you develop hair loss, anxiety, weight loss, or fast heart rate, you may be suffering from an overactive thyroid. On the other hand, hair loss, weight gain, fatigue or brain fog may mean your thyroid has become underactive. It is a good idea to seek specialist advice as your thyroid can recover with the correct treatment.
Many women have experienced severe stress during lockdown and this can trigger raised levels of male hormones to be secreted from the adrenal gland. In some women this can trigger “female pattern hair loss” where there is widely spread thinning of the hair, mainly on the crown of the scalp. This is potentially treatable if caught early on. Another consequence of lockdown and working from home over the past year is weight gain. This has led to multiple sources of fitness and diet advice for quick weight loss, but physical stress has an impact on hair, and that includes radical dieting such as cutting carbs and excessive exercise. Carbohydrate is the body’s most easily usable source of energy. When energy reserves are limited, the body will direct what little it has towards vital organs, and sacrifice non-essential tissue such as hair. Sudden weight loss or excessive exercise can trigger hair shedding, but it usually stops if the diet is improved.
Furthermore, radical changes in diet may lead to nutritional deficiencies – iron, vitamin D or zinc. Low iron levels (or ferritin) will also affect your hair and even if a blood test shows you’re not actually anaemic, being at the low end of the range for ferritin will impact on your hair. Similarly, vitamin D and zinc are required for hair regrowth.
If you have been infected with Covid-19 in recent months and are struggling with ongoing symptoms or changes such as hair loss, weight changes or fatigue, I would recommend seeking medical advice. Getting help sooner rather than later is crucial to correct hormonal imbalances so that you can feel better. If you notice hair loss, it is a good idea to observe it for a few weeks to see if there’s a pattern, but don’t leave it more than three or four months before seeking treatment, as after that, hair follicles can become permanently dormant, reducing your chances of hair growing back.
