Chronic radiodermatitis occurs with chronic exposure to "sub-erythema" doses of ionizing radiation over a prolonged period, producing varying degrees of damage to the skin and its underlying parts after a variable latent period of several months to several decades. In the past this type of radiation reaction occurred most frequently in radiologists and radiographic technologists who were constantly exposed to ionizing radiation. Restated, chronic radiodermatitis, squamous and
basal cell carcinomas may develop months to years after radiation exposure. Clinically, chronic radiodermatitis presents as atrophic indurated plaques, often whitish or yellowish, with telangiectasia, sometimes with hyperkeratosis

Hyperkeratosis

Hyperkeratosis is thickening of the stratum corneum, often associated with a qualitative abnormality of the keratin, and also usually accompanied by an increase also in the granular layer...

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