I only saw one scaly dry area on temple & then doctor said actinic keratosis and another spot on nose. how can dr. see this and what is diffuse ak?

Actinic keratoses: Actinic keratoses are small scaly patches of skin usually seen on the face and usually only on ageing skin (more common after age 50). These lesions are pre-malignant and is large enough should be removed. The doctor usually makes this diagnosis by viewing the lesions and then biopsying them. Diffuse actinic keratoses (diffuse AK) is a condition where there are multiple AK lesions on the body.