Radiation Dermatitis

Radiation dermatitis is skin injury from ionising radiation. It occurs in 85 to 95 percent of patients receiving breast, head and neck, or chest wall radiotherapy, and after interventional fluoroscopy, accidental exposure and radiological incidents. Radiation damages basal keratinocytes, hair follicles, sebaceous and sweat glands, and dermal vasculature, and triggers an inflammatory cytokine cascade.

Acute injury appears within 90 days. Erythema occurs after about 2 Gy, dry desquamation after 8 to 12 Gy, moist desquamation after 15 to 20 Gy, and ulceration and necrosis with doses above 25 Gy.

Chronic changes appear months to years later: atrophy, telangiectasia, fibrosis, hyperpigmentation or hypopigmentation, and late ulceration.

Risk factors are:

• skin folds
• large breasts
• obesity
• smoking
• concurrent chemotherapy (taxanes, anthracyclines)
• cetuximab
• connective tissue disease

Radiation recall can follow later chemotherapy in a previously irradiated field.

• Grade 1: faint erythema or dry desquamation.
• Grade 2: moderate to brisk erythema and patchy moist desquamation, mostly in skin folds, with moderate oedema.
• Grade 3: confluent moist desquamation over 1.5 cm or more, not confined to folds, with pitting oedema.
• Grade 4: skin necrosis or ulceration of full thickness, bleeding, risk of life threatening infection.
• Symptoms: itch, burning, pain, tightness, weeping and secondary infection.
• Late: telangiectasia, atrophy, fibrosis, contracture, lymphoedema, chronic non-healing ulcer, and risk of radiation induced skin cancer (basal and squamous cell carcinoma, sarcoma) after 10 years.
• Red flags: fever, purulent discharge, spreading erythema, necrosis, severe pain, bleeding.

• Clinical diagnosis from the radiation history (dose, field, timing) and the confined area of change matching the treatment portal.
• Grade the skin at each visit by an agreed scale.
• Swab culture for bacterial infection (Staphylococcus aureus, Pseudomonas) when exudate, purulence or fever; herpes simplex PCR for vesicles.
• Biopsy for non-healing ulcers or nodules at least 6 months after radiotherapy to exclude recurrent cancer or radiation induced malignancy.
• Exclude cellulitis, contact dermatitis, drug eruption, graft versus host disease, radiation recall, and cutaneous metastasis.

• General measures: wash gently with lukewarm water and mild soap, pat dry, wear loose cotton clothing, avoid sun, friction, heat and adhesive tape on the field; continue moisturising aqueous cream twice daily.
• Grade 1 to 2: mometasone furoate 0.1 percent cream applied thinly once daily to the field (intact skin) from the start of radiotherapy and continued for 2 weeks after the end; this lowers severity and itch. Hydrocortisone 1 percent twice daily is a milder alternative.
• Moist desquamation: non-adherent silicone or hydrogel dressing changed every 1 to 3 days, soft silicone foam dressings, saline soaks; silver sulfadiazine 1 percent applied twice daily for 7 to 14 days where infection is suspected (avoid during radiotherapy sessions or remove before treatment); avoid occlusive tapes.
• Infection: flucloxacillin 500 mg orally every 6 hours for 7 days (children 12.5 to 25 mg/kg every 6 hours); if penicillin allergic, clindamycin 450 mg orally every 8 hours for 7 days; MRSA suspected: doxycycline 100 mg orally twice daily for 7 days.
• Pain: paracetamol 1 g orally every 6 hours; add gabapentin 300 mg orally at night, titrated every 3 days to 300 mg three times daily for neuropathic pain; topical lidocaine 5 percent patch for localised pain.
• Itch: cetirizine 10 mg orally once daily at night.
• Grade 3 to 4: pause radiotherapy, admit for wound care, debridement, and plastic surgery referral for flap cover after fibrosis; hyperbaric oxygen 2.0 to 2.4 atmospheres for 90 minutes daily for 30 to 40 sessions for refractory late ulcers.
• Late fibrosis: pentoxifylline 400 mg orally three times daily combined with tocopherol 1000 IU orally once daily for 6 to 12 months; physiotherapy and massage.
• Pigment and telangiectasia: pulsed dye laser at 6 to 8 week intervals for 2 to 4 sessions.
• Follow up: weekly skin review during radiotherapy, then at 2 weeks, 6 weeks, 3 months, and yearly for late effects.
• Counselling: avoid sun exposure on the field for life, use broad spectrum sunscreen (SPF 50), and report any new nodule or non-healing wound.