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A study of 2.4 million health records suggests the World Health Organization’s set of 33 long covid symptoms may be too limited
Hair loss may be a long covid symptom
Adem Demir / Alamy
Hair loss, reduced libido and ejaculation difficulties may be unrecognised symptoms of long covid, according to a study of 2.4 million electronic health records.
The World Health Organization (WHO) defines long covid as a set of 33 symptoms that usually develop within three months of a SARS-CoV-2 infection, with the symptoms lasting at least two months with no alternative explanation.
Studies into long covid vary in their definition of the condition, but generally suggest it affects about 5 to 20 per cent of people who have had covid-19. These studies also suggest that long covid encompasses a wider range of symptoms than is officially recognised by the WHO.
“We explored the effect of covid-19 on 115 symptoms of which we found 62 symptoms to be statistically significantly associated with covid-19 at 12 weeks [or more] after infection,” says Anuradhaa Subramanian at the University of Birmingham in the UK. “Some of these new symptoms, like reduced libido, sexual dysfunction and hair loss, are really new. They had not been attributed to covid-19 in the longer term before.”
Subramanian and her colleagues analysed the health records of 486,149 people who tested positive for covid-19 between January 2020 and April 2021 – when the alpha variant was dominant in the UK – but weren’t hospitalised. These primary care records were compared with those of around 1.9 million people who hadn’t tested positive for covid-19. The participants were matched for a range of factors, including age, sex, ethnicity, socioeconomic status, smoking status, body mass index and any other health conditions, such as high blood pressure.
The participants who tested positive for covid-19 were more likely to report any of the study’s 62 symptoms at least 12 weeks post-infection, compared with those who hadn’t tested positive for covid-19. These symptoms included hair loss, reduced libido and ejaculation difficulties.
“In addition to premature, delayed and retrograde ejaculation [when semen enters the bladder instead of emerging from the penis], our definition includes painful ejaculation, late ejaculation and fear of ejaculation,” says Subramanian.
How exactly covid-19 leads to hair loss is unclear, but this can be triggered by other infections such as seasonal flu and stressful events.
“When your body is in a state of stress, it can result in new hair growth, which actually paradoxically, causes your existing hair to fall out,” says Shamil Haroon at the University of Birmingham. “This is a condition called telogen effluvium. In this [condition] it’s not like a single patch of hair, but rather it’s kind of generalised hair loss, so that is one potential mechanism for covid-related hair loss.”
Problems with ejaculation and decreased libido are common in other chronic conditions, such as diabetes, but how exactly sexual dysfunction may develop after a viral infection isn’t well understood.
“People with other chronic illnesses frequently experience sexual dysfunction and we find the same with covid-19, suggesting covid-19 is a chronic illness,” says Haroon. “But we haven’t looked at other viral infections in the way that we’ve looked at long covid and I think this is what long covid has made us realise, that viral infections are not just acute events.”
The team’s analysis also revealed that people with long covid tend to have one of three types of the condition. Most commonly, people experienced a broad range of symptoms, including fatigue, rash and pain, which together affected about 80 per cent of the participants who had had covid-19.
More than one in 10 (14.2 per cent) mainly had cognitive symptoms, including depression, anxiety, insomnia and brain fog. And 5.8 per cent of the participants mainly had breathing problems, such as coughing, shortness of breath and wheezing.
Haroon says capturing the full breadth of long covid symptoms and understanding its different types can help clinicians to develop better treatment plans for those with the condition.
Journal reference: Nature Medicine, DOI: 10.1038/s41591-022-01909-w
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