Val Smith was on a river cruise in France when she woke in the early hours feeling incredible itchiness on her arms, torso and legs. ‘I was in agony,’ recalls the former family support worker who lives in Holbury, Hampshire.
‘I couldn’t sleep so I walked to the ship’s main lounge and sat there itching all night. I kept thinking, what has caused this?’
It wasn’t the first time her skin had reacted in this way: a few weeks previously, Val, now 74, had gone to bed feeling very unwell. ‘I woke up itching and felt as if I’d been bitten by 1,000 mosquitos,’ she says. Her body was covered in hives and welts so she took an antihistamine. ‘Next morning it had gone.’
A week later the same thing happened, again in the early hours.
After the third time, on the cruise in 2018, she worked out that each time she’d eaten beef that night.
She searched online and came across posts about alpha-gal syndrome, a condition triggered by a tick bite causing an allergy to red meat. Val thought instantly of the tick bite she’d had seven years earlier.
At the time, Val and her husband Les, now 82, had recently moved to the New Forest to be near family. ‘I’d built a den with my grandchild, and the day after I noticed a small mosquito-sized red mark on my knee.’
The bite got bigger, causing swelling ‘like a plate wrapped around my knee – huge, round and red’, she says.
Val Smith, 74, has alpha-gal syndrome, a condition triggered by a tick bite causing an allergy to red meat
A couple of months later, the bite still swollen, she saw her GP, who sent her to the local hospital to be tested for Lyme disease, an infection caused by ticks carrying the borrelia bacteria.
If treatment (usually antibiotics) is delayed, or it goes untreated, it can lead to painful joints, memory problems and other debilitating symptoms, The test confirmed that Val had Lyme.
What she didn’t realise was that, as well as causing her leg to swell, the infection prompted an immune response called alpha-gal syndrome (AGS), an allergy to meat that can be triggered after someone is bitten by a tick carrying alpha-gal, a type of sugar molecule, in its saliva.
In response, some people produce antibodies against alpha-gal, ‘in which case we call the person ‘sensitised’, explains Andrew Whyte, a consultant allergist and immunologist at Derriford Hospital, Plymouth.
‘The alpha-gal molecule is also present in the muscles of all mammals – except for humans and most primates – so a sensitised person may have a reaction to alpha-gal when they eat red meat.’
AGS is, he says, ‘completely unrelated’ to Lyme disease, which is ‘an infection rather than an allergy’.
In the US, during tests carried out between 2010 and 2022, more than 110,000 people tested positive for the antibodies to alpha-gal, according to the Centers for Disease Control and Prevention in July, although it’s thought the true figure is closer to 500,000, with cases rising.
While there are no figures in the UK, ‘it’s probably more common than we think as the diagnosis is often missed, but specialists are seeing more cases,’ says Dr Whyte.
He adds: ‘The onset of AGS after a tick bite is often four to six weeks but it can take months in some cases, although we don’t know why. Of course, if there is a very long delay it may be that the person was bitten by a tick but didn’t notice.’
Another feature of AGS is that the symptoms can be delayed by a few hours after eating the red meat. ‘Typically an allergic reaction occurs within an hour of eating [the food that causes it], but in AGS it can often be up to four to six hours,’ says Dr Whyte.
In Val’s case, the reactions occurred around seven hours later.
AGS is most common in the south and southeast regions of the US where a specific tick, called the Lone Star, is ‘the source of alpha-gal transfer to humans’, says Dr Whyte.
It’s also been reported in many other countries, adds Professor Hasan Arshad, chair in Allergy and Clinical Immunology, Clinical and Experimental Sciences at the University of Southampton.
AGS symptoms can range from mild – such as a rash and swelling – to severe, including difficulty breathing and anaphylaxis, where blood pressure drops dangerously and the organs can fail. ‘But it’s entirely possible that you could have sensitisation to alpha-gal and not react or not have any clinical manifestations,’ says Professor Arshad.
Alpha-gal syndrome is a condition triggered by a tick bite causing an allergy to red meat
While alpha-gal is found mainly in ‘mammalian’ meat (ie; not chicken) and organs (for example kidney), milk and gelatine can also contain it, he explains. ‘Hence, drugs and vaccines and even sweets that have mammalian cells/tissues or even a minor quantity of gelatine can occasionally cause a reaction.’
He adds: ‘It’s been reported that people with blood group A and O are at higher risk – and blood group B are protected.’ This is because those with blood type A and O have antibodies which can react to alpha-gal, he explains.
When someone with AGS eats red meat their reaction may be delayed if they eat fatty rather than lean cuts (as it takes longer to digest fats).
Many with AGS ‘may have mild symptoms and never been diagnosed’, Professor Arshad adds. ‘And there may even be some patients with severe symptoms who suffer anaphylaxis but their anaphylaxis has been diagnosed as idiopathic [without any discernible cause] rather than connecting it to meat, as the reaction occurs several hours after consumption of the food.
‘In about 30 per cent of those with anaphylaxis, a cause is not identified,’ he says.
Professor Arshad adds that ‘diagnosis is often delayed, because the condition is uncommon, and allergy as a subject is not taught well in medical schools’. But once AGS is suspected, diagnosis is ‘relatively easy’ with a blood test that can be done by a GP.
After the cruise, Val went to her GP who said she’d ‘probably had a heat rash’. ‘It was only when I got home I realised I should have mentioned AGS so I called and asked if she’d heard of it.’
Her doctor replied that ‘it was not in the UK’. In fact, while the condition was originally identified in the US in 2002, the UK is among the many other countries where it has now been found.
Dr Whyte says: ‘While Lone Star ticks are mostly responsible for AGS in North and Central America, other species can be involved in other parts of the world.’
Val carried on eating meat but noticed the reaction started happening ‘even when I ate pork and sausages or bacon – anything with four legs!’ she says. ‘I’d have worse and worse skin reactions.’
Later in 2018, Val insisted on being referred to an allergy specialist. A blood test showed she had Grade 4 AGS, meaning she is ‘strongly positive’ for it (the scale runs from one, ‘equivocal’, to four) – ‘that explained why I reacted so badly every time’, she says.
She was referred to her hospital’s immunology department, where she was warned the reaction can get worse and prescribed an EpiPen (a device loaded with a shot of adrenaline to reduce severe allergic reactions).
She was told to avoid all red meat. ‘This extends to anything from a mammal, such as gelatine or fat. So many foods contain these, such as certain sweets, desserts, even toothpaste, as well as some vaccines so I have to be extra careful.’
As Professor Arshad explains: ‘There is no cure for alpha-gal syndrome so people affected need to avoid meat strictly.’
He said life can be difficult for those who have a severe allergy. ‘The reaction can occur with even small amounts of meat or even inhalation of fumes when meat is cooked, as airborne molecules of alpha-gal can be inhaled.’
Val adds: ‘It’s very hard at hotel buffets as there can be cross-contamination from spoons and utensils and I have to check the food labels on everything.
‘I thought the idea of a tick causing all this was ridiculous and that I was going mad. I hope my story raises awareness that AGS is in the UK.’
