When palpated, the lip may have a texture similar to rubbing the gloved finger along sandpaper.AC may occur with skin lesions of actinic keratosis or skin cancer elsewhere, particularly on the head and neck since these are the most sun exposed areas. Rarely it may represent a genetic susceptibility to light damage (e.g. xeroderma pigmentosum or actinic prurigo). Causes
AC is caused by chronic and excessive exposure to ultraviolet radiation in sunlight. Risk factors include:

Outdoor lifestyle: e.g. farmers, sailors, fishermen, windsurfers, mountaineers, golfers, etc. This has given rise to synonyms for this condition such as "sailors lip" and "farmers lip". The prevalence in agricultural workers in a semi-arid region of Brazil is reported to be 16.7%. Light skin complexion: the condition typically affects individuals with lighter skin tones, particularly Caucasians living in tropical regions. In one report, 96% of persons with AC had phenotype II according to the Fitzpatrick scale. Age: AC typically affects older individuals, and rarely those under the age of 45. Gender: the condition affects males more commonly than females. Sometimes this ratio is reported as high as 10:1.Additional factors may also play a role, including tobacco use, lip irritation, poor oral hygiene, and ill-fitting dentures. Diagnosis
Tissue biopsy is indicated. Prevention
To prevent AC from developing, protective measures could be undertaken such as avoiding mid-day sun, or use of a broad-brimmed hat, lip balm with anti UVA and UVB ingredients (e.g. para-aminobenzoic acid), or sun blocking agents (e.g. zinc oxide, titanium oxide) prior to sun exposure.
Actinic cheilitis  is cheilitis (lip inflammation) caused by long term sunlight exposure. Essentially it is a burn, and a variant of actinic keratosis which occurs on the lip. It is a premalignant condition, as it can develop into squamous cell carcinoma (a type of mouth cancer). Signs and symptoms
AC almost always affects the lower lip and only rarely the upper lip, probably because the lower lip is more exposed to the sun. In the unusual cases reported where it affects the upper lip, this may be due to upper lip prominence. The commissures (corners of the mouth) are not usually involved.Affected individuals may experience symptoms such as a dry sensation and cracking of the lips. It is usually painless and persistent. The appearance is variable. White lesions indicate hyperkeratosis. Red, erosive or ulcerative lesions indicate atrophy, loss of epithelium and inflammation. Early, acute lesions may be erythematous (red) and edematous (swollen). With months and years of sun exposure, the lesion becomes chronic and may be grey-white in color and appear dry, scaly and wrinkled.There is thickening whitish discoloration of the lip at the border of the lip and skin. There is also a loss of the usually sharp border between the red of the lip and the normal skin, known as the vermillion border. The lip may become scaly and indurated as AC progresses.