When you have radiation treatment for cancer, you may have some changes in your skin in the area being treated. Your skin may turn red, peel, or itch. You should treat your skin with care while receiving radiation therapy.

External radiation therapy uses high-powered radiation or particles to kill cancer cells. The radiation rays or particles are aimed directly at the tumor from outside of the body. Radiation therapy also damages or kills healthy cells. During treatment, skin cells do not have enough time to grow back between radiation sessions. This causes side effects to the skin.

Side effects depend on the dose of radiation, how often you have the therapy, and the part of your body the radiation is focused on, such as:

• Abdomen
• Brain
• Breast
• Chest
• Mouth and neck
• Pelvis (between the hips)
• Prostate
• Skin

Two weeks or so after radiation treatment starts, you may notice skin changes such as:

• Red or "sun burned" skin
• Darkened skin
• Itching
• Bumps, rash
• Peeling
• Temporary or permanent hair loss in the area being treated
• Thinning or thickening of skin
• Soreness or swelling of the area
• Sensitivity or numbness
• Skin sores

Most of these symptoms will go away after your treatments have stopped. However, your skin may remain darker, drier, and more sensitive to the sun. When your hair grows back, it may be different than before. Some areas of hair loss may be permanent.

When you have radiation treatment, a health care provider may use permanent ink dots, or tattoos on your skin. These indicate where to aim the radiation.

Take care of your skin in the treatment area.

• Wash gently with a mild soap and lukewarm water only. Don't scrub. Pat your skin dry.
• Don't use lotions, ointments, makeup, or perfumed powders or products. They can irritate skin or interfere with treatment. Ask your provider what products you can use and when.
• If you normally shave the treatment area, only use an electric razor. Don't use shaving products.
• Don't scratch or rub your skin.
• Wear loose-fitting, soft fabrics next to your skin, such as cotton. Avoid tight-fitting clothes and rough fabrics like wool.
• Don't use bandages or adhesive tape on the area.
• If you are being treated for breast cancer, do not wear a bra, or wear a loose-fitting bra with no underwire. Ask your provider about wearing your breast prosthesis, if you have one.
• Don't use heating pads or cold packs on the skin.
• Ask your provider if it's OK to swim in pools, salt water, lakes, or ponds.

Keep the treatment area out of direct sunlight while undergoing treatment.

• Wear clothes that protects you from the sun, such as a hat with a broad brim, a shirt with long sleeves, and long pants.
• Use sunscreen.

The treated area will be more sensitive to the sun. You will also be more at risk for skin cancer in that area. Tell your provider if you have skin changes and any break or openings in your skin.

Doroshow JH. Approach to the patient with cancer. In: Goldman L, Cooney K, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 14.

National Cancer Institute website. Radiation therapy and you: support for people with cancer. www.cancer.gov/publications/patient-education/radiationttherapy.pdf. Updated April 2021. Accessed June 18, 2024.

Zeman EM, Schreiber EC, Tepper JE. Basics of radiation therapy. In: Niederhuber JE, Armitage JO, Kastan MB, Doroshow JH, Tepper JE, eds. Abeloff's Clinical Oncology. 6th ed. Philadelphia, PA: Elsevier; 2020:chap 27.