The condition, also known as nosemaphobia or hypochondriasis, is one of the most common reasons people seek therapy through Anxiety UK. The charity believes cases of health anxiety have been exacerbated in the modern era by Dr Google, with the worried searching their symptoms online and often wrongly concluding that a minor symptom is really a sign of serious illness.
Nicky Lidbetter, chief executive of Anxiety UK, says: "Health anxiety can be a vicious circle and if you constantly check your body for signs of illness, such as a rash or bump, you'll eventually find something, often following this up with a Dr Google appointment.
"Often it won't be anything serious - it could be a natural body change, or you could be misinterpreting signs of anxiety such as increased heart rate and sweating, as signs of a more serious condition. "This form of self-diagnosis is a key factor behind the rise of health anxiety."
What is health anxiety?
A person with health anxiety has persistent concerns about a specific illness or disease, such as cancer, HIV or heart disease, fearing they are already unwell or worrying they're eventually going to get a diagnosis they don't want to hear.
"It can also be a constant fear or worry about a series of health conditions that causes health anxiety," explains Lidbetter. "It's very natural for us all to worry about any form of illness and that could rise or fall depending on other stress or anxiety. But if the anxiety or worry is wholly focused on a preoccupation with a serious illness, despite reassurance from your GP or other medical professionals, then it would be classed as health anxiety."
What are the signs of health anxiety?
People with health anxiety are likely to be extremely aware of minor symptoms such as headaches, joint pain or sweating, and think they're symptoms of a serious medical complaint.
This can lead to stress and spark a vicious cycle, as stress can cause symptoms including headaches, nausea and pain, leading to worries that further symptoms of the feared disease are developing.
Sufferers may become nervous and obsessed with frequently checking possible symptoms. Some may need constant reassurance, complaining of their symptoms to friends and family, and visiting the doctor regularly, despite tests showing everything is normal.
Other sufferers may avoid visiting the doctor altogether, because they're frightened of hearing bad news. They may also be reluctant to share their fears with loved ones, either because they're afraid of having their fears confirmed, or because they believe they won't be taken seriously.
"As with many forms of anxiety or phobias, the impact of health anxiety can range from it being a constant frustration that impacts on day-to-day quality of life, to being extremely debilitating," says Lidbetter.
"For some, the anxiety becomes chronic, and they may spend many hours checking for symptoms, seeking reassurance from others, surfing the internet for information about different diseases, or repeatedly visiting the doctor."
What causes health anxiety?
Knowing someone with a serious illness may be a trigger for health anxiety, but there are many other possible causes for the condition to develop, including a family history of a particular long-term or chronic illness such as cancer or heart disease.
Other triggers may include negative experiences in childhood, publicity campaigns around specific illnesses, or general anxiety leading to concerns about health.
Links to OCD
Health anxiety and obsessive compulsive disorder (OCD) can sometimes be linked, because health anxiety sufferers can rapidly go from fearing illness to becoming obsessed about illness, convincing themselves that every ache and pain is a sign of something sinister.
Anxiety UK says that when health anxiety has its roots in OCD, sufferers often change the illness they're worried about. For example, many young people with health anxiety initially worry about HIV, but as they get older they begin to worry about cancer and heart disease instead. For this reason, it's important that treatment doesn't just focus on alleviating concerns about a specific disease, as the sufferer could then begin to worry about a completely different disease instead.
What's the treatment?
Health anxiety is treatable, but recovery can take some time. Initially it might help to have a thorough check-up with a GP to help calm fears about specific illnesses. Talking therapy such as cognitive behavioural therapy (CBT), prescribed anti-depressant medication, or a combination of both is the most common form of treatment.
Local self-care and self-help support groups can help with finding ways to manage the condition, and Lidbetter notes that self-help books can be useful.