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Why do people with Ehlers-Danlos Syndrome (EDS) call themselves "Zebras"? This is based on an old medical quote stating "when you hear hoofbeats thing horses not zebras". This is based a bit on Occam's razor which is a principle which forms the basis of methodological reductionism, also known as the principle of parsimony. The simplest explanation is that one should not make more assumptions than needed - that the simplest explanation is the likeliest.

Of two equivalent theories or explanations, all other things being equal, the simpler one is to be preferred.

So what does this have to do with EDS and medicine? So in the old hoofbeats saying the zebra is the rare disorder. When doctors are students learning about all these rare and wonderful disorders they often want to make that one in a million rare call. So medical students are often taught that it's more likely that it's a common disorder presenting uncommonly than a rare disorder presenting commonly. The problem is there are more than 7000 rare diseases which impact 8% of Australians. So doctors are likely to run across a rare disease at some stage in their medical career. So while it's important for them to learn not to jump to the rare disease they have to remember we still exist. Doctors need to remember that sometimes the simpliest explanation is actually the rare disorder

Simplicity is the ultimate sophistication.

EDS as a whole is considered a rare disorder with some types of EDS having only a handful of people diagnosed. So the zebra became the mascot and used on awareness ribbons for EDS and other rare disorders. Unfortunately many people have been told they can't have EDS as it's rare. So you may hear someone with EDS calling themselves a "medical zebra" and the phrase "dazzle together" as a group of zebra is called a dazzle.

A ribbon with black and white zebra stripes bent over itself into and awareness ribbon shape
EDS Awareness Ribbon

While the hoofbeats is a helpful phrase, especially early in a med students life they also need to know Hickam’s Dictum.

patients can have as many diseases as they damn (or darn) well please


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