Menu

What Is Human Tree Disease?

Medically Reviewed by Dan Brennan, MD on May 18, 2021

Epidermodysplasia verruciformis (EV) is sometimes called "tree-man disease" or "human tree disease." It's a very rare syndrome that causes bark-like lesions to grow on your skin. The lesions are disfiguring and can grow so large that they become disabling.

A Palestinian man had lesions that left him unable to use his hands in a recent case of human tree disease. Doctors had to do multiple surgeries to remove the lesions. The growths can come back over time. Surgeons expect that he will need more operations in the future.

The condition was first identified in 1922. It is so rare that doctors can only confirm 200 cases of it since then. EV is a genetic disorder that can't be predicted. There are no tests for human tree disease.

What Is Epidermodysplasia Verruciformis?

The main symptoms of human tree disease are the bark-like growths on the skin. It also leads to other symptoms and an increased risk of additional health problems.

Skin lesions. The growths may look flat and wart-like or appear as reddish-brown plaques. They might have a mottled appearance or look like brown sunspots. They tend to show up on your trunk, neck, face, hands, and feet. 

EV growths can become very large. They can also overlap one another. That gives them the bark-like appearance that caused the nickname of human tree disease. The growths can cover large portions of some people’s bodies and limit their movement.

Pain. The lesions may extend well below the surface of your skin. They can compress your nerves and cause pain.

Cancer Risk. People with human tree disease are at high risk for certain types of skin cancer. More than half of the people with EV developed skin cancer by the time they were in their 40s or 50s. Squamous cell carcinomas were the most common skin cancer types in people with EV.

Causes of Human Tree Disease

The cause of EV is a genetic mutation that prevents your body from fighting off infections. Doctors believe it is an autosomal recessive mutation.

Autosomal recessive means that both of an affected person's parents carry the mutation without any symptoms of it. They have a 25% chance of having an unaffected child, a 50% chance of having a child who also is a carrier with no symptoms, and a 25% chance of having a child with symptoms.

The mutation associated with human tree disease also makes people susceptible to human papillomaviruses (HPV). There are over 100 strains of HPV. Some can cause mild symptoms such as warts. Some other strains of HPV are associated with certain cancers. Most types of HPV are harmless. Many people never show any signs of them.

People with EV are not able to clear HPV from their systems. Doctors have found HPV5 and HPV8 in growths on most of the known cases of EV.  

The strains of HPV found in people with human tree disease are not the same strains associated with cancer. They also aren’t the strains that the HPV vaccine prevents.

Treatment for Epidermodysplasia Verruciformis

Human tree disease is so rare that doctors don't have a lot of methods for treating it. They have tried using medications, freezing the growths, and burning them off using chemicals. None of those have been effective.

Surgery to remove the growths has been helpful in the short term. But people have had the growths come back over time. Doctors recently treated a man with EV by carefully removing the entire growth including the parts below the skin. They suspected that the growths would be less likely to come back if the entire root was removed.

Doctors also thought that the man spread the virus to new areas whenever he touched the growths and then touched another one of his body parts. They removed the existing growths completely to prevent new ones from developing later.

Human tree disease is not a condition that affects many people. It remains a medical mystery in many ways. Researchers may find more effective treatments for it in the future.

WebMD Medical Reference

Sources

‌SOURCES:

The Canadian journal of plastic surgery: "Epidermodysplasia verruciformis: An early and unusual presentation."

Genetic and Rare Diseases Information Center: "Epidermodysplasia verruciformis."

Mayo Clinic: "Autosomal recessive inheritance pattern."

National Cancer Institute: "Gardasil 9 Vaccine Protects against Additional HPV Types,” "HPV and Cancer."

NPR: "Patient With 'Tree Man' Syndrome Says He 'Can Finally Live A Normal Life."

© 2020 WebMD, LLC. All rights reserved.