Upper respiratory allergies and inflammation and swelling of the adenoids, the tissue at the back of the nose, can cause poor fluid drainage from the middle ear to the external ear and therefore cause a blockage in the Eustachian tube. Excess fluid can lead to middle ear congestion.
1 Black skin and Asian skin have thicker and more compact dermis than white skin. This is also why blacks and Asians have fewer facial wrinkles than whites. 2  Black skin has more casual lipids and more moisture in the stratum corneum than white skin.  Black skin has 50% lower ceramides than white or Hispanic skin.
For example, in North America the term black people is not necessarily an indicator of skin color or ethnic origin, but is instead a socially based racial classification related to being African American, with a family history typically associated with institutionalized slavery.