Key points
- Most people having radiotherapy develop skin changes in the treated area: redness like sunburn, darkening, dryness, itching or peeling [1, 3].
- These changes usually appear a few weeks after treatment starts, and many of them improve a few weeks after it ends [1].
- Shower every day with lukewarm water and mild soap and pat your skin dry; in studies, washing the skin did not make skin reactions worse [1, 3, 5].
- In studies, deodorant did not increase skin reactions during breast radiotherapy; ask your treatment team before you start [1, 6, 7].
- Blisters, open sores or wet, painful skin should be reported to your radiotherapy team the same day [1, 2].
Why does the skin change during radiotherapy, and when?
Radiation also destroys healthy skin cells in the treated area. Because radiotherapy is given almost every day, the skin cells do not have enough time to recover [1]. That is why most people having radiotherapy develop skin changes, and about 1 in 3 have a moderate to severe reaction with moist peeling [3].
- Redness or darkening of the skin, like sunburn or a tan
- Itching, sometimes severe
- Dryness and peeling
- Swelling of the skin
- A "moist reaction": wet, sore skin that can become infected; most often in skin folds such as under the breast, behind the ears and on the buttocks, or where the skin is thin, such as the neck
Timing: changes usually appear a few weeks after radiotherapy starts, and many of them go away a few weeks after treatment ends. Some changes may last: the skin in the treated area may stay darker or blotchy, drier or thicker, and will always burn more easily in the sun [1].
How strong the reaction is depends on the radiation dose, the size and location of the treated area, chemotherapy given at the same time, body weight, smoking and skin colour [3].
Daily skin care: what should I do?
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Wash every day
You can shower every day with lukewarm water and use a mild soap. If you prefer a bath, take one every other day and keep it short. Dry your skin with a soft towel by patting, not rubbing. Take care not to wash off the marks drawn on your skin for radiotherapy [1].
In studies, washing the skin with soap and water did not make skin reactions worse [3, 5].
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Moisturise
Use the cream or lotion your treatment team recommends so that your skin does not become dry and itchy. Apply it after a shower, while your skin is still slightly damp. Products containing alcohol or fragrance can dry out or irritate the skin [2]. Ask which products you should not apply just before a radiotherapy session [1, 2].
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Soft, loose clothing
Choose clothes and sheets made of soft fabric, and do not wear tight clothing that does not breathe over the treated area [1].
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Keep out of the sun
Cover the skin of the treated area from the sun every day, even on cloudy days: a wide-brimmed hat, long sleeves and trousers. Ask your team about sunscreen, usually SPF 30 or higher. Keep doing this after radiotherapy has finished, and avoid sunbeds [1].
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If the anal area is being treated
After a bowel movement, clean yourself with a baby wipe or water instead of toilet paper, and ask whether sitting in a shallow bowl of lukewarm water (a sitz bath) would help you [1].
What can the doctor do?
Your team checks your skin during your sessions; tell them about any change you notice [1]. Depending on the state of your skin, they may use:
- Steroid creams: in a review of the studies, steroid creams such as mometasone and betamethasone lowered the chance of moist peeling and severe skin reactions [8].
- Special films and dressings: some thin adhesive films are recommended to prevent skin reactions (particularly in breast radiotherapy), and soft dressings to care for damaged skin [4].
- Other medicines: lotions for dryness and itching, antibiotics for infection, and medicines to reduce swelling or itching [1].
- A shorter course of radiotherapy: in breast cancer, one study found that a shorter course with a higher daily dose caused fewer skin reactions than the usual course [9].
When should I contact a doctor?
Tell your radiotherapy team the same day if:
- Your skin has blistered, an open sore has formed, or it is wet and oozing [1, 2].
- Redness or pain is getting worse, or sores have become painful and wet; such sores can become infected [2].
- Itching or pain is so bad that it keeps you awake or stops your daily activities [1].
- Any skin change worries you; some changes can be serious [1].
Call straight away if you have a temperature of 38 °C or higher, especially if you are also having chemotherapy [10].
Frequently asked questions
Can I shower during radiotherapy?
Can I use deodorant?
In several studies of breast radiotherapy, deodorant did not increase skin reactions [6]. In a review of all these studies, deodorants and antiperspirants had no effect on skin reactions, itching or pain, and the authors saw no reason to advise against them [7]. Ask your own treatment team as well [1].
Which cream should I use?
The one your treatment team recommends. Products without alcohol or fragrance are best [2]. Many products have been tested for preventing skin reactions; for most of them research is limited or the results have differed, and a few options, such as steroid creams, have helped in studies [3, 8]. Ask before using any new product [1].
When will the darkening of the skin fade?
Many changes improve a few weeks after treatment ends, but the skin in the treated area may stay slightly darker, drier or thicker for good [1].
Do I still need to avoid the sun after radiotherapy has finished?
Yes. The skin in the treated area will always burn more easily; cover it or use sunscreen every day, and avoid sunbeds [1].
Related pages
Acute radiation dermatitis: the evidence (for doctors)
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- MASCC guideline 2023 (Delphi consensus, 42 experts, 75% consensus threshold): six interventions were recommended for prevention: photobiomodulation therapy and Mepitel film in breast cancer, Hydrofilm, mometasone, betamethasone and olive oil; for management of dermatitis, Mepilex Lite dressings. Most interventions were not recommended because of insufficient or conflicting evidence or lack of consensus [4].
- MASCC systematic review: 235 studies including 149 randomised trials. Acute dermatitis develops in up to 95% of patients and about 36% have moderate to severe reactions with moist desquamation. Based on several trials, deodorant (including aluminium-containing products) and washing with soap and water do not worsen dermatitis, although there is no evidence to support their use for prevention [3].
- Washing: randomised trial of 99 patients with breast cancer: moist desquamation 14% with washing with soap and water vs 33% without washing; washing was not associated with increased toxicity [5].
- Deodorant: non-inferiority trial of 84 patients: grade 2 axillary dermatitis 23% vs 30% and breast dermatitis 30% vs 34% (with vs without deodorant), no grade 3 or 4; less sweating with deodorant [6]. Meta-analysis of 5 trials: grade 1 or higher dermatitis OR 0.81 (95% CI 0.54 to 1.21), grade 2 or higher OR 0.90 (0.65 to 1.25), grade 3 OR 0.54 (0.26 to 1.12) [7].
- Topical corticosteroids: meta-analysis of 10 trials (1041 patients; 6 studies of mometasone and 4 of betamethasone): reduction in moist desquamation OR 0.34 (95% CI 0.25 to 0.47); betamethasone OR 0.29 and mometasone OR 0.39; a similar finding for grade 2 or higher dermatitis [8].
- Hypofractionation in the breast: trial of 287 patients, 42.56 Gy in 16 fractions vs 50 Gy in 25 fractions (both with a boost): grade 2 or higher acute toxicity 47% vs 78%; dermatitis, pruritus and hyperpigmentation were also lower with the shorter course [9].
Related cancer types
References
10 referencesShow all referencesClose the reference list
Numbers in the text, such as [1], refer to these sources. Sources with a “Study card” button are summarised in the site’s evidence library.
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- 10Infection and Neutropenia during Cancer Treatment
This page is based on reputable scientific sources and was last updated on 28 October 2026. The content of this website is for educational and informational purposes only and does not replace consultation, diagnosis or treatment by a specialist physician. Consult your treating physician about any treatment decision.
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