A high power view of solar elastosis showing the typical bluish discoloration of the superficial dermis in a case of long term exposure to sun-light.
Actinic keratosis is, as the name implies, associated with sun exposure.
Long term exposure to the sun is the causative factor. Believed to represent a response of the skin to UV rays. The lesion may appear as a roughened area of skin with some evidence of hyperemia and a tendency to ulceration. Histologically, the actinic keratosis lesion may be visualized as a carcinoma in situ of the skin. Thus, instead of the normal orderly progression of basal layer, stratum spinosum, granular cell layer, stratum corneum, there is a loss of polarity of cells.