Effects of UVR on lips

One of the effects of UVR, in causing degeneration of the collagen fibres in the dermis, is to destroy the white ridge or roll of skin at the point where the skin and red mucosa of the lips meet.  This ridge is formed by dermal collagen fibres.  UVR damage across the breadth of the lower lip, causes a loss of the lip contour through loss of elastic tissue, and also causes premalignant change often necessitating removal of quite large segments of the red mucosa of the lip.

Lip cancer is usually in the form of squamous cell carcinoma and begins as a thickening in the lip sometimes around an ulcer or crack