In the UK, a condition is usually called rare when it affects fewer than 1 in 2,000 people. That sounds unusual, but there are thousands of rare conditions, and together they affect around 3.5 million people in the UK.
Because each condition is uncommon, most GPs will only see a handful of cases in a whole career. That is one of the reasons a diagnosis can take years, and why families often see several different specialists before a condition is named.
A long wait for a diagnosis is not a sign that you are imagining things or that nobody is trying. It usually means the tests that would give an answer are expensive, slow, or only available in a few hospitals.
If you think something has been missed, it is reasonable to ask three questions: what else could this be, what test would rule that in or out, and who else could look at this with us?
If something here worries you
This is general information. For advice about your own health or medicines, speak to your GP or pharmacist.
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