Sun & Skin News

How Skin Conditions Can Affect Skin Cancer Detection and Treatment

By Arielle Grabel • March 5, 2019
skin conditions

Millions of Americans are affected by skin cancer, but millions more are battling skin conditions like rosacea, eczema, psoriasis and melasma. Although bothersome, these conditions are usually harmless and manageable through ongoing treatment.

In dealing with my own bout of melasma, I got to thinking — can these skin problems make it harder to spot a potential skin cancer? Can a dermatologist treat a patient’s condition and skin cancer simultaneously? I asked James Sandwich, MD, MPH a board-certified dermatologist practicing in Fayetteville, Georgia, to break down these conditions for us and how they impact skin cancer diagnosis and treatment.

Rosacea

Rosacea is an inflammatory condition that affects 16 million Americans. Its main features include redness, visible blood vessels and bumps that form mostly on the face. “Rosacea can both imitate and mask different forms of skin cancer,” explains Dr. Sandwich. Two common skin cancers, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), often appear as red patches on the skin, similar to rosacea.

“I recently saw a patient who was misdiagnosed with rosacea on the nose,” says Dr. Sandwich. “A biopsy revealed a BCC, and a relatively large flap had to be used for reconstruction after removal of the cancer.” Late detection like this can lead to many complications where the tumor can cause disfigurement and potentially spread. While it may be a bit difficult to distinguish between BCC and rosacea, Dr. Sandwich points out that skin cancers are more likely to bleed from minimal trauma (such as washing or toweling); rosacea usually will not.

There are medications available that can control rosacea, and sun protection should be part of any treatment plan. Continual treatment of an outbreak is key when it comes to skin cancer removal. If the skin is badly inflamed, it can make removing a tumor more technically difficult and result in higher recurrence rates. “A Mohs surgeon would remove the tumor as usual; however, when viewing the tissue under a microscope, the tumor cells may be obscured by the inflammatory cells. Therefore, the tumor may not be completely removed, as it is ‘hidden’ from view,” explains Dr. Sandwich. The surgeon might need to perform multiple surgeries to ensure all the cancer is removed.

Eczema and Psoriasis

Affecting almost 40 million Americans collectively, eczema and psoriasis are inflammatory conditions that appear very similar to each other. “These two often pose as diagnostic dilemmas to experienced dermatologists due to their structural overlap,” says Dr. Sandwich.

Eczema is red and often scaly plaques on the skin. In patients with long-standing eczema, the skin can become itchy, thickened and form nodules. Psoriasis mirrors these symptoms and can also include pustules on the hands and feet. “Due to inflammation and scale, a skin cancer diagnosis can be delayed in these patients, especially by non-dermatologists,” says Dr. Sandwich.

One of the issues associated with removing skin cancer in any area of inflammation is the possibility that inflamed skin can harbor bacteria. “Most physicians will excise skin cancers on inflamed skin, unless it is grossly infected,” says Dr. Sandwich. If the infection is not yet cleared, bacteria can be introduced into the treatment site and delay healing. “In a case where excision should be delayed, the area can be treated with oral and topical antibiotics prior to the surgery.”

Topical medications, such as corticosteroids used to control the condition, should be paused during skin cancer treatment as they could impair skin healing. “Corticosteroids inhibit fibroblast growth (cells crucial to human development), which is needed for wound healing,” says Dr. Sandwich. “They also hinder the immune response, which can increase the risk of infection and promote cancer cell growth.” Doctors usually recommend reintroducing these medications several weeks after skin cancer surgery.

In addition to topical medications, these conditions can be treated with controlled doses of UV light. “This helps with itching and can actually improve the disease; however, the risk of developing skin cancer will increase,” says Dr. Sandwich. The dermatologist may use excimer laser, or what’s called narrow-band UVB, to spot-treat skin plaques. The doctor typically uses a limited dose while protecting the rest of the patient’s body with sunscreen or protective sheets and clothing, though there are cases where the physician may recommend treating the entire body.

People with eczema and psoriasis may be extra sensitive to sunscreen, which can exacerbate symptoms. However, patients can and should still use sunscreen. For these patients, Dr. Sandwich recommends physical sunscreens that contain zinc oxide and titanium dioxide. Sunscreens labeled specifically ‘for sensitive skin’ may be better for these people as well.

Melasma

Melasma is characterized by large brown spots on the skin, and affects 6 million Americans, 90 percent of whom are women. It is triggered by the sun, pregnancy and other hormonal changes, making it much harder to treat than other forms of hyperpigmentation.

Given its coloring, melanoma and other skin cancers can ‘hide’ in patches of melasma. “A patient of mine had been treated by a spa for what was thought to be a benign pigmented lesion that actually turned out to be melanoma,” says Dr. Sandwich.

Melasma is often treated with lightening agents like hydroquinone, which can lighten the appearance of a cancer and make the borders less distinct, making them harder to spot and treat.

Removal of skin cancer on a patient with melasma would generally be the same as if it were on a clear part of the skin, but it can pose some minor issues. “Determining the margins for excising a melanoma can be difficult, and single malignant cells will sometimes extend well beyond the clinically apparent margin,” says Dr. Sandwich. As a precaution, the surgeon may remove more skin than usual.

Topical medications to treat melasma should not interfere with skin cancer removal. Some more advanced treatments, however, should be avoided pre, during and post-op. “Treatments such as laser or chemical peels generally would not be recommended in the immediate surgical period,” says Dr. Sandwich.

Sunscreen is a mainstay therapy for melasma and can prevent the pigmented cells from appearing in the first place. Because the disease can occur anywhere on the body, patients should follow a full sun protection regimen from head to toe.

The Bottom Line

Having one of these skin diseases does not inherently increase skin cancer risk, but it can make skin cancer harder to spot. The Skin Cancer Foundation recommends that all adults visit a dermatologist annually for a full-body skin exam, and this is especially important for people experiencing any of these conditions. Dermatologists not only help manage these diseases effectively but will also keep a trained eye out for signs of skin cancer. It’s also important to perform monthly skin self-exams at home. If you notice anything new, not healing or unusual (whether it’s within an affected area or not), you should bring it to your dermatologist’s attention as soon as possible.

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