Skin changes in the middle years are relatively minor but are often regarded as major problems. Wrinkles, skin dryness and hair loss are sources of great concern for some individuals. Little can be done to prevent hair loss, since it is primarily determined by genetic factors. Wrinkles and thinning of the skin can best be prevented by avoiding sun exposure. Seborrheic keratoses, skin tags, hyperplastic sebaceous glands and angiomas appear more often in patients over age 40 and must be distinguished from malignant lesions.