Zebras vs Horses: What is a Zebra?

I have been asked a lot recently what Zebras have to do with Ehlers Danlos Syndrome. A Zebra in the medical world is someone with a rare and highly complex condition, such as EDS:

 “When you hear the sound of hooves, think horses, not zebras.” (Ehlers-Danlos Support UK, Why the Zebra)

The expression above is hammered into medical students throughout their doctoral training. The analogy serves to remind them that the simplest explanation and diagnosis for an illness,

"We are a Rainbow of Possibilities" by Rosie P

(the horse) is often the right one. As a result, when diagnosing a patient, doctors learn to expect relatively common ailments. Rare gets forgotten. This tends to lead to years of misdiagnosis, sheer ignorance and sometimes the sufferer being forgotten altogether and pushed from pillar to post with little in the way of answers.

Diagnosis usually comes years later, from some bright spark who considers rare and embraces it.

One of the things that makes EDS hard to diagnose is no two sufferers present in exactly the same way. Just as no two zebras bare exactly the same pattern of stripes on their coats. Some have different types of EDS. Others with the same type may have only joints affected, whereas others joints are fine but their internal organs are not. There are an infinite number of combinations, each unique to the person they belong to.

“Sometimes when you hear hoofbeats, it really is a zebra.” Ehlers Danlos Sufferers are known as Zebras. Unique, rare and proud. 

"Why the Zebra?" Explanation poster from dailykos.com

Sources: Ehlers-Danlos Support UK (2017), Why the Zebra- Ehlers-Danlos Support UK, [online] Available at https://www.ehlers-danlos.org/about-us/charity-aims-and-focus/why-the-zebra/ (Accessed 7 February 2018)

The Ehlers Danlos Society (2017), Why the Zebra- Ehlers Danlos Society, [online] Available at https://www.ehlers-danlos.com/why-the-zebra/ (Accessed 7 February 2018)