Sunken cheeks are just another example of how our facial features age. Sunken cheeks occur when a person doesn't have a lot of flesh between the bony arch of cheek under the eyes (zygoma) and the lower jawbone (mandible). As we grow older, we lose facial fat which gives our cheeks a youthful ‘plumpness’.
Although age is a major cause of sunken cheeks there are a number of other things which may result in this condition.
You may develop hollow cheeks due to illness, such as Ehlers-Danlos syndrome (an inherited condition caused by collagen defects), lipoatrophy (a loss of facial fat commonly associated with HIV), advanced tuberculosis and eating disorders such as anorexia or bulimia nervosa.
Other causes of hollow cheeks include dehydration, malnutrition, smoking, a lack of sleep, and harsh weather conditions. You may also find you have sunken cheeks after weight loss.
Sunken cheeks are not exclusive to one particular sex as both men and women can have them.