Bowen's disease, also called squamous cell carcinoma (SCC) in situ, is a primitive kind of skin cancer. It occurs due to aberrant growth, division, and accretion of cells present in the epidermis of the skin (outer layer of skin). They do not spread, but if left untreated, Bowen's disease has chances of developing into SCC, a common skin cancer that is curable.

Bowen's disease appears as red patchy areas of skin ranging from a few millimeters to several centimeters. It looks like a plaque or a papule on the skin. Sometimes the plaque may crack and result in bleeding. Although no clear picture is available about the causes of this disease, it is definitely not a result of allergy and is not heritable and communicable. Bowen's disease is found more common in people aged above 50 — 60 and women are specifically at high risk.

Primary Causes

In most cases, Bowen's disease comes under the category of primary lesions. Risk of Bowen's disease generally arises due to higher exposure of the skin to ultraviolet radiation. People with fair skin and those spending long durations in the outdoors are at greater risk than those with high melanin pigmentation. Patients using immunosuppressants also show proneness to the condition.

The major suspected causes of Bowen's disease are as listed below:

Human Papilloma Virus

The sexually transmitted human papilloma virus (HPV) is found to be one of the causes of Bowen's disease. Patients having cutaneous HPV infection are highly susceptible to the disease. HPV is a family of over 150 associated viruses, of which HPV 16, 18, 34, and 48 are cancer-inducing agents. Especially, HPV 16 is most often associated with Bowen's disease, and is also a cause of cervical cancer. Other HPVs cause Bowen's disease in other parts of the body. Sometimes, the virus sets off in the finger nails and in between the fingers. Not all people with Bowen's disease do have HPV.

Immunity Suppression Drugs

Malignancy on skin is very common in immunocompromised patients. Recipients of organ transplantation procedure are at high risk of developing SCC in situ as they intake immunosuppressant drugs in order to avoid organ rejection. Patients with autoimmune diseases, chronic leukemia, and immune destroying infections are also identified to be affected by Bowen's disease.

Arsenic Ingestion

Arsenic metal is extensively distributed in the environment, primarily through water. It is widely used in the manufacture of glass, alloys, insecticides, fungicides, and coloring agents and is used in the powdered form in agriculture for crop dusting and wine growing. Consumption of arsenic-contaminated food and water results in arsenic poisoning, and chronic exposure to it may lead to skin malignancies such as Bowen's disease and basal cell carcinoma. Bowen's disease can develop in individuals after 10 years of arsenic exposure, while other skin cancers may manifest after a dormancy duration of 20–30 years.

Ionizing Radiation

In the 20th century, ionizing radiation was also stated to be an inducing agent of Bowen's disease. Nowadays, it is commonly found in people associated with radiology, who do not make proper use of protective gloves or aprons. Also, the risk of Bowen's disease is found to be very high in patients with a record of radiotherapy treatment, for example, cancer patients.

Bowens disease, pigmented by Dr. Harald Kittler

Overexposure to Sunlight

A number of research studies show evidence of Bowen's disease as a consequence of over-exposure to sunlight. The adolescent male skin (especially of those who do outdoor works) is shown to be more prone to this type of squamous cell carcinoma in situ compared to females, which can be corrected by varying the lifestyle and following healthy moisturizing habits.

Chronic exposure to ultraviolet (UV) rays from the sun, which may be work-related exposure, is primarily responsible for developing SCC in situ. On exposure, UV radiation involves in mechanisms such as inactivation of p53 suppressing genes, which in turn cause aggressive development of skin malignancies like Bowen's disease.

Secondary Causes

Some other causes of Bowen's disease could be a previous record of skin damage, inflammation on any part of the skin, or aging of skin.

• Previously injured skin that is prone to repeated damage or prolonged scarring may induce the risk of Bowen's disease.
• Conditions like inflammations on the skin may, in rare cases, be connected to the start of Bowen's disease. This condition is commonly termed as eczema.
• Finally, aging skin, where melanin and other protective layers present in the epidermis are much reduced, may be prone to increased risks for developing Bowen's disease.

People presenting with symptoms of Bowen's disease will have a superior prognosis. This disease is highly responsive to treatment and develops subtle immunity against cancerous cell production. In addition, there is very less chance of getting affected (3–5%) after progressive treatment.