Grade 3 radiation dermatitis in a patient with presumed latent actinic lichen planus

Radiation-induced skin injury ranges from acute dermatitis to chronic skin changes. Acute skin injury occurs during the course of radiation treatment and may take 1 to 3 months after the completion of radiation therapy to completely heal. Patients with mild acute dermatitis present with mild erythema, dry desquamation, pruritus, hyperpigmentation, and hair loss. Severe acute dermatitis is characterized by confluent moist desquamation, ulcers, hemorrhage, and necrosis. Chronic radiation-induced skin injury includes chronic fibrosis with associated skin breakdown and infection. The severity of radiation-induced skin toxicity depends on radiation factors (dose, fractionation, volume, and surface area) and patient-specific factors. Excessive skinfolds increase radiation-induced skin toxicity. Also, patients with poor nutrition status or a preexisting vascular condition or connective tissue disease have impaired wound healing and are at increased risk of skin toxicity. Actinic lichen planus is an autoimmune skin disease characterized by a violaceous papule rash. Here, we report the case of a patient with presumed latent actinic lichen planus treated with definitive radiation therapy who subsequently developed overt lichen planus and severe radiation dermatitis in the treatment fields.