Radiodermatitis — Skin Irritation from Radiation Therapy

Radiodermatitis is a localised toxic effect on the integumentary system that develops when ionising radiation depletes basal epithelial stem cells and triggers cutaneous inflammation. Therapeutic radiation generates reactive oxygen species, damages cellular DNA, and alters microvascular permeability in the dermis. Consequently, the normal rate of epidermal cell shedding surpasses the rate of basal cell replenishment.

Clinically, radiodermatitis is classified into acute and chronic stages. Acute radiodermatitis presents within days to weeks of initiating radiotherapy and is graded from mild erythema and dry desquamation (flaking) to severe moist desquamation (weeping, denuded skin) and ulceration. Chronic radiodermatitis can emerge months or years later, characterised by dermal fibrosis, epidermal atrophy, telangiectasia, and altered pigmentation.

Up to 90% of individuals undergoing external beam radiation experience some degree of skin irritation. Uncontrolled radiodermatitis causes substantial physical discomfort, sleep disruption, and anxiety, and can increase the risk of secondary skin infections. If skin breakdown becomes severe, doctors may need to pause radiotherapy sessions, which could compromise cancer control. Proactive, gentle skin care helps protect the skin barrier and prevents treatment interruptions.

Radiodermatitis is evaluated through direct clinical examination using standardised grading scales, such as the Common Terminology Criteria for Adverse Events (CTCAE) or the Radiation Therapy Oncology Group (RTOG) criteria. Routine laboratory biomarkers are not used for diagnosis, although bacterial or fungal wound swabs may be taken if secondary infection is suspected in broken, weeping skin.

Radiodermatitis can occur whenever radiation beams pass through the skin, but it is most frequently observed in breast cancer, chest wall irradiations, and head and neck malignancies due to superficial target volumes. It also regularly affects individuals undergoing radiotherapy for skin cancers, anal or vulval cancers, soft tissue sarcomas, and Hodgkin or non-Hodgkin lymphomas.

Management focuses on preserving skin integrity and relieving discomfort. Recommendations include washing gently with mild, unscented soap, applying non-irritating, water-based barrier creams, and avoiding friction, extreme temperatures, or sun exposure. For moderate-to-severe symptoms, topical corticosteroids, non-adherent silicone dressings, or hydrogel dressings may be prescribed, and any secondary bacterial infections are promptly treated with antibiotics.