Our skin is a remarkable, living shield, constantly repairing and regenerating itself. However, sometimes we notice a persistent patch on our skin, a spot that looks like a rash but never seems to heal. While it’s easy to dismiss such a spot as a minor irritation like eczema or psoriasis, it can sometimes be a sign of something more significant. One such condition is Bowen’s disease, a very early form of skin cancer. Though the term “skin cancer” can be frightening, Bowen’s disease is non-invasive and highly treatable, especially when identified early. Understanding this condition is the first essential step toward effective management and peace of mind.

Bowen’s disease is a form of early-stage skin cancer, specifically squamous cell carcinoma in situ. That means the cancerous cells are confined to the outermost layer of the skin (the epidermis) and haven’t spread deeper. It appears as a persistent, scaly, red patch or plaque that may look like eczema or psoriasis, often on sun-exposed areas like the lower legs, hands, or face.

Though it’s a type of skin cancer, Bowen’s disease is highly treatable when caught early.  It is considered a precancerous condition or a Stage 0 cancer. However, it is not something to ignore. If left untreated over a long period, there is a small but significant risk, estimated to be around 3-5% that the abnormal cells can break through the “soil” (the basement membrane separating the epidermis from the dermis) and become an invasive squamous cell carcinoma.

Analogy: Think of Bowen’s disease like a weed growing only on the surface of a garden bed, it hasn’t spread its roots yet. If you catch it early, you can pull it out easily without damaging the soil. But if ignored, it may grow deeper and become harder to control.

Bowen’s disease, like most skin cancers, develops when the DNA within skin cells becomes damaged. This damage disrupts the normal cell life cycle, causing the cells to grow and multiply uncontrollably. While several factors can contribute to this DNA damage, the vast majority of cases are linked to one primary culprit: long-term exposure to ultraviolet (UV) radiation from the sun.

1. Ultraviolet (UV) Radiation: Cumulative sun exposure over a lifetime is the single most significant cause of Bowen’s disease. Every time our skin is exposed to the sun without protection, UV rays penetrate the epidermis and can damage the genetic material in our skin cells. Our bodies have mechanisms to repair this damage, but over many years, the damage can accumulate, overwhelming these repair systems. This is particularly relevant for individuals living in sun-rich countries, where intense, year-round sun exposure is a part of daily life. It’s not just about intentional sunbathing; years of incidental exposure from walking, driving, or working outdoors all contribute to the cumulative dose of UV radiation.

2. Human Papillomavirus (HPV): While the sun is the main cause for lesions on sun-exposed skin, certain strains of the human papillomavirus are a primary cause for Bowen’s disease that appears on the genitals or around the anus. When it appears in these areas, it is sometimes referred to by a more specific name, Bowenoid papulosis. The HPV strains linked to this are often the same high-risk types associated with other cancers, including cervical cancer.

3. Immunosuppression: A weakened immune system is less capable of detecting and destroying abnormal cells, including cancerous ones. Individuals who are immunosuppressed have a significantly higher risk of developing Bowen’s disease and other skin cancers. This includes people who:

• Have had an organ transplant and are taking immunosuppressant drugs to prevent rejection.
• Have medical conditions that weaken the immune system, such as chronic lymphocytic leukemia or HIV/AIDS.
• Are undergoing chemotherapy.

4. Arsenic Exposure Though much less common today, long-term exposure to inorganic arsenic, either through contaminated drinking water, certain industrial processes, or past medical treatments, has been linked to the development of Bowen’s disease.

Clinically, it’s common to notice that patients with a history of sun damage or outdoor work are at higher risk, especially on the lower legs and hands.

Understanding what causes Bowen’s disease helps us identify the factors that make someone more likely to develop Bowen’s disease. This condition doesn’t happen overnight; it is the result of accumulated damage and risk over many years.

The individuals most at risk are those who:

• Have Extensive Sun Exposure: People who have spent a lot of time outdoors without sun protection, whether for work (like farmers or construction workers) or recreation, are at the highest risk. A history of frequent or severe sunburns also significantly increases the risk.
• Have Fair Skin: People with fair skin, light-colored eyes, and red or blond hair (Fitzpatrick skin types I and II) have less melanin, the pigment that provides some natural protection from UV radiation. They are therefore more susceptible to sun damage.
• Are Older: Bowen’s disease is most commonly diagnosed in older adults, typically over the age of 60. This is because the effects of sun damage are cumulative, taking many decades to manifest as a visible skin lesion.
• Have a Weakened Immune System: As mentioned, immunosuppression from medication or disease is a major risk factor.
• Have a History of HPV Infection: For lesions in the genital area, a history of HPV is a direct risk factor.

Bowen’s disease can be tricky to spot, so it’s often mistaken for common skin problems like psoriasis, eczema, or ringworm instead of being seen as skin cancer. The key difference is its persistence; while other rashes may come and go, a Bowen’s disease patch will remain and typically grow very slowly over months or years.

The classic appearance of a Bowen’s disease lesion includes several key features. It usually appears as a:

• Persistent, reddish, or pink patch on the skin.
• Slightly scaly or crusty surface.
• Clearly defined but often irregular border.
• Slow-growing lesion, which may eventually reach several centimeters in diameter.
• Flat or slightly raised plaque.

These patches are usually asymptomatic, meaning they don’t cause pain or itching, which is another reason they can go unnoticed for a long time. They may occasionally crack and bleed, especially if irritated by clothing. While they can appear anywhere on the skin’s surface or mucous membranes, they are most often found on sun-exposed areas like the lower legs, arms, hands, face, and neck.

If you have a suspicious skin patch that is not healing, it is crucial to have it evaluated by a doctor, preferably a dermatologist.

Diagnosis

The diagnostic process is straightforward. A dermatologist will first perform a clinical examination, looking closely at the lesion, possibly with a dermatoscope (a special magnifying lens). A skin biopsy represents the sole method to confirm Bowen’s disease diagnosis because its appearance remains highly suggestive of the condition.

A biopsy is a simple procedure, usually done in the doctor’s office under local anesthesia. A small sample of suspicious tissue is removed and sent to a laboratory. A pathologist then examines the cells under a microscope to determine if they are abnormal and if they are confined to the epidermis, which confirms the diagnosis of Bowen’s disease (SCC in situ).

Treatment

Since Bowen’s disease is a non-invasive cancer, there is a wide range of highly effective treatment options available. The goal of every treatment is to completely remove the abnormal cells. The best choice depends on several factors, including the lesion’s size, location, thickness, and number, as well as the patient’s overall health and preference.

Common treatment options include:

• Photodynamic Therapy (PDT): This two-step treatment involves applying a special light-sensitizing cream to the lesion. A few hours later, a specific wavelength of light is shone on the area, which activates the cream and selectively destroys the abnormal cells.
• Topical Chemotherapy or Immunotherapy: For some lesions, treatment may involve applying cream at home for several weeks. 5-fluorouracil (5-FU) is a chemotherapy cream that destroys rapidly dividing cells. Imiquimod is an immunotherapy cream that stimulates the body’s own immune system to attack the abnormal cells.
• Cryotherapy: This involves spraying liquid nitrogen onto the lesion to freeze and destroy the abnormal cells. It is a quick procedure but can sometimes be less effective for thicker lesions.
• Curettage and Electrodessication: In this common procedure, the dermatologist scrapes off the lesion with a sharp, spoon-shaped instrument (a curette) and then uses an electric needle to burn the base, destroying any remaining abnormal cells and stopping the bleeding.
• Surgical Excision: This involves cutting out the entire lesion along with a small margin of healthy skin to ensure all abnormal cells are removed. The wound is then stitched closed. Excisional surgery has one of the highest cure rates and allows a pathologist to confirm that the entire lesion was removed.

Bowen’s disease represents one of the earliest and most treatable stages of skin cancer. While the diagnosis can be unsettling, its “in situ” nature means it is a localized issue confined to the skin’s surface, posing no immediate threat to your overall health. However, its potential to progress to an invasive cancer makes treatment essential. The wide variety of effective treatment options means that a dermatologist can tailor a plan that is right for you, leading to excellent outcomes.

The most important takeaway is to be vigilant about your skin health. Pay attention to any new or changing spots, especially a persistent patch that doesn’t heal. In a sunny environment, consistent sun protection is the best defense against developing Bowen’s disease and other skin cancers. If you have a concern, don’t delay, a simple check-up can lead to an early diagnosis, better treatment, and lasting peace of mind.

• American Academy of Dermatology Association (AADA). (n.d.). Squamous cell carcinoma in situ. Retrieved from https://www.aad.org/public/diseases/skin-cancer/types/common/scc/in-situ

• National Institutes of Health (NIH). (n.d.). Bowen disease. Genetic and Rare Diseases Information Center. Retrieved from https://rarediseases.info.nih.gov/diseases/5943/bowen-disease

• Skin Cancer Foundation. (2024). Squamous cell carcinoma (SCC). Retrieved from https://www.skincancer.org/skin-cancer-information/squamous-cell-carcinoma/