Epidermodysplasia verruciformis (EV) is an extremely rare skin condition that can cause bark-like growths.
While the exact prevalence of EV is unclear, there have been more than 200 reported cases, the Genetic and Rare Diseases Information Center (GARD) note.
When EV is severe enough to cause bark-like growths, it is sometimes colloquially called “tree man syndrome.” This is a misnomer for obvious reasons, but also because it affects both males and females.
Here, we look into what EV is, as well its symptoms, causes, treatments, complications, and the outlook.
Most people come into contact with HPV at some point, and having EV compromises a person’s immune function in a way that makes them more likely to develop the infection.
Over time, the infection causes skin growths, such as viral warts and pigmented, inflamed patches. In severe or extreme cases, a person may develop bark-like growths.
HPV is contagious and usually transmitted through skin-to-skin contact. A person can pass it on even if they experience no symptoms.
The most striking symptom of EV is bark-like growths of tissue, which most commonly develop on the hands and feet. However, it is important to note that this is a severe presentation.
People with EV tend to develop:
- small pink, white, reddish-brown, dark brown, or violet growths called papules, which may be raised and flat-topped
- larger scaly, raised, or inflamed patches of skin called plaques, which may have irregular edges
- raised brown growths called viral warts
The warts tend to occur in clusters of a few to more than 100 lesions each. They commonly form on areas exposed to the sun, including the:
Larger plaques associated with EV tend to form on the:
However, people with EV can experience symptoms anywhere, including the:
- soles of the feet
- external genitalia
In about 10% of EV cases, the person’s parents were relatives.
Rarely, the condition can either be linked to sex, in the sense that the mutation developed on the X or Y genes, or it can be autosomal dominant — caused by a single mutated gene.
Also, acquired EV has developed in people with:
According to the GARD, EV seems to occur due to a loss-of-function mutation in one of two adjacent genes, called EVER1/TMC6 and EVER2/TMC8.
These genes help facilitate the transportation of zinc in skin cells. Zinc, meanwhile, plays an important role in immune function.
Some research indicates that the mutations linked with EV may make it easier for the virus to access cellular zinc stores.
The GARD also note that mutations associated with EV seem to make people extremely susceptible to infections with beta forms of HPV, which usually do not cause infection in healthy people.
As EV is an inherited condition, a person is not able to prevent it from developing.
However, a person can take certain steps to reduce symptoms and help limit the chances of the lesions becoming cancerous.
Though there is no cure for EV, some medications, therapies, and lifestyle changes may help make symptoms more manageable and reduce the chances of complications.
Medical management options include:
- Systemic or topical retinoids: These medications may help prevent an HPV infection from spreading and reduce skin inflammation. Taking 0.5 to 1.0 milligrams of acitretin daily for 6 months may be the most effective treatment.
- Interferon-alpha: This contains a natural compound that reduces cell growth and division, especially in cancer cells. It can also help treat viral infections.
- Cholecalciferol: This medication is similar to vitamin D.
Lifestyle changes that may help include:
- Sun avoidance or protection: Avoiding sun exposure, covering up as much as possible, and wearing sunscreen may help prevent skin cancer from developing.
- Quit smoking: Smoking increases the risk of developing several types of cancer and reduces overall immune function.
Also, a doctor may recommend the following ways to remove growths:
- Cryotherapy: This involves freezing off growths.
- Laser surgery or electrosurgery: These employ either lasers or high-frequency electrical currents to remove or destroy growths and other lesions.
If a growth is cancerous, a doctor may recommend surgery to remove it. In some cases, this requires a skin graft.
Lesions will continue to develop throughout a person’s life.
Roughly 30–60% of people with EV also develop non-melanoma skin cancers.
This tends to happen in a person’s 40s or 50s, and the cancer tends to develop in sun-exposed regions. Squamous cell carcinoma (SCC) is especially prevalent among people with EV.
Common symptoms of SCC include:
- thick, scaly, rough patches of skin
- open sores with raised borders
- growths that resemble warts
- sores that develop in older areas of scarring
- firm, dome-shaped growths
- brown areas that appear similar to age spots
- a growth that may resemble a tiny horn
According to GARD, people with black skin tend to have a lower chance of developing skin cancer.
Most tumors associated with SCC remain local or do not spread.
According to a 2019 article, the types of HPV that healthcare professionals typically associate with the development of skin cancer in people with EV are: HPV 5, 8, 17, 20, and 47 — especially types 5 and 8.
EV is a lifelong condition, and there is currently no cure, though some medical treatments and lifestyle changes may help manage symptoms or reduce the risk of cancer.
Getting an early EV diagnosis, managing symptoms, and practicing cancer prevention methods can help reduce the risk of serious complications.
EV does not affect life expectancy, provided that the person receives effective treatment for any cancerous lesions that may develop.
EV, known colloquially as tree man syndrome, is an incredibly rare genetic condition. It leads to chronic HPV infections that result in characteristic skin growths and lesions.
People who may have EV or a family history of it should notify a doctor, ideally a specialized dermatologist, as soon a possible. The goal is to manage symptoms and prevent severe complications. A person may also benefit from genetic counseling.