A constant blast of air on your body may cause dry skin. Lotions and moisturizers will help prevent this, but if your skin is excessively dry, use caution and monitor your skin to make sure you’re not over drying it.
Another thing to consider is that some people sleep with their eyes partially open.
Weird, but it does happen.
Again, a steady airstream will dry your eyes and may cause major irritation.
If you wear contact lenses when you sleep, this is particularly problematic.
Some people also sleep with their mouth open, and the excess airflow will potentially dry out their mouths and throats.
Source Daily Express :: Health Feed