One of the most famous fictional detectives of all time is Sherlock Holmes. Holmes uses his extraordinary skills of observation to crack seemingly impossible cases.


What you might not know is that Sir Arthur Conan Doyle, the creator of Sherlock Holmes, studied medicine at the University of Edinburgh before becoming a writer, and based his character – at least partially – on a former university teacher called Joseph Bell. Bell was, apparently, particularly brilliant at spotting things other doctors had missed.

The ability to use observation and deductive reasoning to help make an accurate diagnosis is at the heart of medicine. It is also at the heart of my new BBC series, called Diagnosis Detectives.

In this series, we’re bringing together 12 of the UK’s leading medical experts to help people whose symptoms have baffled other doctors. Each of our specialists is a leading light in their field. The idea is that by combining their expertise and, where appropriate, bringing in cutting-edge technology, we should be able to give our patients the answers they so desperately crave.

As you can imagine, this was a difficult series to make, so all credit must go to the production team who pulled it together. First, they had to find suitable patients, who had a genuine, mystery illness and who were in great need. Then we had to hope that our crack team of experts would be able to make a diagnosis.

Let me give you an example of what our experts were up against. At the beginning of the programme, we met Paul, a 75-year-old from London.

Eighteen months ago, he woke up with a swollen, puffy right eye. He went to see his GP, who did a test for conjunctivitis, that was negative. Next, he was referred to Moorfield’s Eye Hospital.

© Jason Raish
© Jason Raish

They diagnosed inflammation of the eyelid, and he was given topical creams, as well as oral antibiotics. The swelling went away but then came back with a vengeance.

Our experts wondered if it could have been triggered by something he’d bought, a new shampoo or a change of washing powder? Our rheumatologist noticed that he had vitiligo – essentially the loss of skin pigment in some areas.

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The number of possible diagnoses began to grow, and any life-threatening diseases had to be rapidly excluded.

In the end, the experts were able to establish that it wasn’t cancerous and it wasn’t anything contagious.

In fact, the final diagnosis was that he had sarcoidosis, a rare condition that causes small patches of red and swollen tissue to develop, particularly in organs like the lungs and skin. It is not curable, but it is certainly treatable. So, another case solved, and a sense of relief for the patient.



Dr Michael Mosley is former medical doctor, health writer and BBC presenter. He’s best known as presenter of Trust Me I’m a Doctor on BBC Two but has also written a number of bestsellers about personal health and medicine, including The Fast Diet, Fast Asleep and Fast Exercise.