Bizarre Diseases You Won’t Believe Really Exist

The average American develops a number of chronic health problems at some point in their lifetime. While many of these diseases can be prevented, there are plenty of less common conditions some people can’t avoid.

These rare diseases — everything from growing extra limbs to being allergic to the sun — actually exist. Have you heard of any of them?

Tree man syndrome

A man with Tree Man Syndrome sits on a bed.

Living a normal life is difficult, but possible. | YouTube

This rare condition can cause a person’s skin to develop raised bumps, lesions, and inflamed patches that sometimes resemble tree bark or roots. There are treatments to relieve symptoms, but there isn’t any way to stop its development.

Next: This disease adds up to more fingers and toes.


Woman peeking through fingers.

Many people experience this condition. | Camrocker/iStock/Getty Images

People with oligodactyly have fewer than five fingers and/or toes. The condition opposite of oligodactyly, polydactyly, occurs when a person develops more than five fingers on either or both hands or more toes than normal.

Next: Have you ever lost control of your own body? That’s what happens when this syndrome occurs.

Alien hand syndrome

A hand with a red fingernail pointing at a wall.

The person might lose control of their hands entirely. | Kmatija

Rarely, a person can randomly feel like they’re losing complete control of one of their hands. When alien hand syndrome develops, it can seem as though one hand starts functioning separately from the mind. This happens most often after a stroke or brain surgery.

Next: Most humans have two arms and two legs, making this disease extremely jarring and rare.


A young girl with Polymelia sits on a bed wearing a black shirt and jewelry.

This is a rare condition. | YouTube

Children with polymelia are born with extra limbs due to a birth defect. Any human or other animal has a small chance of experiencing this phenomenon. In some cases, doctors can surgically remove the extra arms or legs depending on their location and size.

Next: Some rare diseases cause unbearable body odor.

Fish odor syndrome

Fishes swimming in an ocean.

A difficult condition to live with. | User10095428_393/iStock/Getty Images

When the body can’t break down trimethylamine, a compound you consume through diet, your sweat, breath, and urine emit an odor similar to rotting fish. Often called fish odor syndrome, this condition results from a genetic mutation. There is no cure.

Next: In rare cases, muscle can turn to bone — which isn’t supposed to happen.

Stone man syndrome

A person with Stone man syndrome sits in front of a house.

It can be fatal. | YouTube

Stone man syndrome slowly turns tendons, ligaments, and muscles to bone, making patients feel as if they are turning into stone. This affects a person’s ability to move freely and live a normal life. Most people lose their lives to this condition by the age of 40.

Next: It’s not normal for legs to swell like this.


Elephantitis can weaken the immune system. | YouTube

Parasitic worm infections can cause a rare condition in which legs, arms, and other body parts swell and enlarge to multiple times their normal size. People with elephantiasis also suffer from weakened immune system and face an increased risk of life-threatening infections.

Next: Werewolves aren’t real, but this condition can make you look like one.

Werewolf syndrome

A young girl with a face covered in hair swims in a pool.

A rare disorder that is still being researched. | YouTube

People living with werewolf syndrome experience excessive hair growth on the face and eyelids in men, and in patches all over the body in women. Officials have documented fewer than 100 cases of this disorder worldwide.

Next: Sometimes, parts of a person’s body start to shrink unexpectedly.

Parry-Romberg syndrome

A young boy with Parry-Romberg syndrome.

It can affect young people as well. | YouTube

Parry-Romberg syndrome causes the skin and soft tissues of half of a person’s face to progressively thin out or shrink. Sometimes, the same affect also starts to occur in other parts of the body on the same side, such as the legs or arms.

Next: This disease turns the skin an unusual color.


A man with blue/gray skin sits during a televised interview.

Not something you’d see everyday. | YouTube

Argyria makes a person’s skin appear blue or grey. This happens because of an over-exposure to silver over a long period of time. The condition isn’t life-threatening — silver exposure doesn’t cause cancer or other health problems — but there is no cure.

Next: This disease changes the color of a person’s hair, skin, and eyes.


A man with Albinism posing while wearing a jacket.

They are able to live normal lives with a few adjustments. | SensSnoW

People living with albinism don’t produce enough or any melanin, the pigment that determines skin color. As a result, many people with this condition have light, sometimes pinkish skin, light or white hair, and a lighter or translucent eye color.

Next: Do you jump when you hear a loud noise? Imagine not being able to control that reaction.


A wife comforts her husband while sitting on a bed.

It can make living a normal life very difficult. |

A person with hyperekplexia responds involuntarily to unexpected stimuli — everything from sudden noise to touch to movement. This makes voluntary movements more difficult, and can even result in interrupted breathing and repeated hernias.

Next: This disease makes a person’s eyes look like they’re dancing.

Nystagmus (dancing eyes)

A person with blue eyes staring straight ahead.

This can affect vision. | Shironosovz/Getty Images

Nystagmus makes a person’s eyes move involuntarily in different directions or “dance.” People with nystagmus often can’t see well as a result. Extreme stress or fatigue can worsen this condition, but doctors often don’t know why it develops in the first place.

Next: People with this disease often have to avoid sunlight.

Vampire syndrome

A person holds their hands out under sunlight.

They will have extreme sensitivity to light. | Ipopba/iStock/Getty Images

People living with porphyria suffer painful sensitivity to sunlight. Some types cause skin rashes that can scar or become infected. Other types can cause confusion or hallucinations, breathing problems, nausea, or chronic pain.

Next: Signs of aging usually don’t appear until later in life. This condition is the exception.


A person holding up a book near a table filled with medical equipment.

Unfortunately, progeria can be very fatal to children. |

Hutchinson-Gilford Progeria Syndrome causes accelerated aging that starts within the first two years of a child’s life. They lose their hair and body fat, develop wrinkled skin, and often suffer from hip dislocations and strokes. The average child with Progeria dies of heart disease by the age of 14.

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