Breast radiation dermatitis (BRD) is a common side effect of radiation therapy for breast cancer. This skin reaction occurs because the high-energy X-rays must pass through the skin to reach the targeted tissue. The acute phase of BRD typically develops within the first 90 days following the start of radiation. It can range from mild redness to open, painful sores.
The Mechanism of Skin Damage
Radiation-induced skin damage begins at the cellular level when high-energy radiation interacts with the water molecules in the skin. This interaction creates reactive oxygen species (ROS), unstable molecules that damage cellular structures, particularly the DNA within the skin cells. The primary targets are the basal keratinocytes, the rapidly dividing stem cells responsible for renewing the outer layer of the skin (the epidermis).
Damage to the DNA of these basal cells disrupts their normal ability to proliferate and differentiate, leading to a loss of the protective epidermal layer. This cellular depletion eventually results in visible skin peeling and breakdown.
Simultaneously, the radiation triggers an inflammatory response characterized by the release of pro-inflammatory cytokines like Interleukin (IL)-1 and IL-6. This inflammatory cascade involves the activation and recruitment of immune cells, contributing to initial symptoms of warmth, redness, and swelling.
Damage to blood vessel cells contributes to the early redness and edema seen in the acute phase. The cumulative effect of this DNA damage and inflammation is the sunburn-like reaction known as radiation dermatitis.
Recognizing the Stages of Skin Reaction
The visual progression of breast radiation dermatitis follows a predictable pattern related to the cumulative radiation dose. The initial stage, often called Grade 1, is characterized by faint or moderate redness (erythema). For patients with darker skin tones, this stage may appear as darkening or hyperpigmentation rather than a bright red color.
This mild reaction typically occurs two to four weeks into the treatment schedule and can be accompanied by symptoms like itching, a burning sensation, and mild swelling. As the radiation dose increases, the damage progresses to Grade 2, visually marked by dry desquamation. This is when the skin begins to flake, peel, or scale, similar to a severe sunburn.
Dry desquamation is often first observed at cumulative doses above 20 Gy, and the skin barrier function is impaired. If the reaction continues to worsen (often at doses above 30 to 40 Gy), the patient may develop Grade 3 dermatitis, the most severe acute reaction. This stage is confluent, moist desquamation, meaning there are open, weeping areas where the top layer of skin has been completely lost.
These painful, moist areas often start in skin folds, such as the inframammary fold or the armpit, due to friction and moisture, and they exude a clear, serous fluid. This open wound creates a significant risk of infection. The pain associated with Grade 3 dermatitis can be severe enough to require an interruption in the patient’s treatment schedule.
Managing Acute Symptoms and Promoting Healing
Managing acute radiation dermatitis focuses on alleviating discomfort, protecting the compromised skin barrier, and preventing infection. Skin care involves gentle cleansing of the treated area with mild, non-perfumed soap and lukewarm water. The skin should be patted dry with a soft towel rather than rubbed to minimize friction and prevent further damage.
Moisturizing the skin is essential. Patients are typically advised to use approved, unscented emollients, avoiding products that contain alcohol, lanolin, or perfumes. Mid- to high-potency topical steroid creams, such as mometasone furoate, are often recommended by the oncology team to reduce inflammation and decrease the severity of the reaction. These steroid creams are typically applied once or twice daily to intact skin, followed by a layer of the approved moisturizer.
For clothing, patients should choose soft, loose-fitting garments to prevent rubbing against the sensitive breast skin. Patients should also avoid applying heat or cold (such as heating pads or ice packs) directly to the treatment area. In cases of moist desquamation, specialized hydrogel dressings or barrier films may be used to protect the open areas and promote healing.
Pain management is a priority, and over-the-counter options are often sufficient for mild symptoms. An oncology team should be consulted for prescription pain relief if needed. Acute symptoms usually peak one to two weeks after the final treatment session. The majority of symptoms resolve completely within two to four weeks following the end of radiation therapy.