Most of us have had occasion to consult Dr Google. Rather than waste a GP's time with your embarrassing worries, just type your symptoms into a search engine, hit return and terrify yourself with the results. I learned an awful lot about Raynaud's phenomenon the day I typed "cold mouse hand" into Google and hit return. But I also learned that the complaint is a common one, so the cause probably was too: when you hear galloping, medical students are told, think horse, not zebra.

Just in case you weren't paranoid enough already, there's a new search engine that eliminates all the reassuring and straightforward diagnoses and concentrates on rare diseases and disorders. FindZebra, is a research project meant for use only by medical professionals, but that shouldn't stop anyone with a computer having a go. In the search box on the home page it says: "Start typing some patient symptoms". That sounds like an invitation to me.

My eyes itch. I type "itchy eyes". There are 20 diagnoses returned, and not one of them is "tiredness". I can choose between Duhring Brocq disease – a rare skin disorder possibly associated with the inability to digest gluten – lichen planus (mostly for women) and Sjögren's syndrome, in which the immune system mistakenly attacks the body's moisture-producing glands. By the time I've decided I have it, my eyes have stopped itching.

"Sore spot on tongue" produces, among other things, toxic epidermal necrolysis, which is exactly as bad as it sounds, and often fatal. On the other hand, I may have Wiskott-Aldrich syndrome, or pemphigus, which I was too scared to read about. Lichen planus also came up again. Now I've got two symptoms.

"Cold mouse hand" – a symptom that instantly returned once I started thinking about it again – did flag up Raynaud's phenomenon, but also paramyotonia congenita of Von Eulenburg, which, for obvious reasons, I prefer. It's genetic, but it doesn't affect longevity, although eating ice-cream could be dangerous.

My search for a classier name for a disease I call Phantom Phone – where a creaking hip leads me to believe my mobile is vibrating in my pocket – proves fruitless, but it does eventually lead me to something called supernumerary phantom limb, a "condition where the affected individual believes and receives sensory information from limbs of the body that do not actually exist, and never have existed". I haven't got it, but I can't help thinking the two diseases are related.

I'm no doctor, and for that reason I recommend FindZebra unreservedly.