Syphilis cases in women going undiagnosed because symptoms like hair loss and brain fog are missed, experts warn – as cases surge in females

Syphilis cases in women have surged over the past decade, with experts warning many infections could be going undiagnosed as symptoms are easily missed.

While most cases in the UK remain among men who have sex with men, the proportion in women has risen sharply, with diagnoses more than tripling over ten years.

The latest UK Health Security Agency (UKHSA) data shows women accounted for just over six per cent of all syphilis diagnoses last year – marking a rise of more than 200 per cent over the same period.

Experts say many female cases go undiagnosed because the infection’s symptoms are subtle and frequently confused with more common conditions.

The early signs – painless sores – are often internal or in hard-to-see areas, meaning they often go unnoticed. When spotted, they are regularly mistaken for herpes, thrush, ingrown hairs or minor skin irritation.

As the disease progresses, a rash can appear on the palms of the hands and soles of the feet, which may be mistaken for eczema, psoriasis, dermatitis or allergic reactions.

Studies also show that, as the disease progresses, patients can develop syphilitic alopecia, where hair begins to fall out. 

One woman in her twenties, who wished to remain anonymous, said she was misdiagnosed for more than two years before finally being tested for syphilis.

She said: ‘I was struggling with an awful range of symptoms – my hair was falling out and I was told it was alopecia. 

‘I had the worst brain fog to the point where they started testing me for autoimmune diseases. My personality changed too – I thought I was having a mental health crisis.

‘It took two years for a doctor to actually test me for syphilis. I thought it was some kind of Victorian disease, not something that I’d ever be at risk of.

‘Fortunately, it was easy to treat and I don’t have any lasting effects but those two years were underpinned by extreme stress and feeling like my body was betraying me. I’ll never get that time back.’

Researchers from Brighton and Sussex Medical School identified similar delays in diagnosis after reviewing cases within an NHS trust.

Their analysis of six patients – including one woman – found multiple missed opportunities to test for syphilis, even after individuals presented with severe symptoms.

These included abscesses, inflamed joints, weight loss, hearing loss, nerve damage and abnormal liver function results. Delays in diagnosis ranged from one month to more than three years.

Syphilis is often referred to as ‘the great imitator’ because it can mimic a wide range of other illnesses. 

Researchers said some patients underwent unnecessary and sometimes invasive investigations as a result, while two experienced ‘severe psychological distress’.

 Although syphilis is easily treatable once diagnosed, untreated infections can lead to serious complications.

The risks are particularly severe for babies born with congenital syphilis, which can cause significant illness or death. While the condition is rare in the UK, screening is recommended for all pregnant women.

Between 2020 and 2024, more than 1,300 pregnant women in England were diagnosed with syphilis.

Valentina Milanova, chief executive and founder of women’s health company Daye, said stigma and misconceptions around testing are contributing to cases being missed.

She said: ‘The way the health system approaches STI testing is worrying. It is often framed as something people do after a scare, rather than a routine part of preventative healthcare.’

‘Many infections can exist without obvious symptoms while continuing to affect the body. By the time some people are diagnosed, they may already be dealing with complications linked to fertility or long-term reproductive health.’

‘There is still a perception that STI testing is only necessary for certain groups or behaviours – but that simply isn’t true. Sexual health should be treated like any other part of routine healthcare.’